Vessel sealer and divider

ABSTRACT

An electrosurgical instrument includes an elongated shaft having opposing jaw members at a distal end thereof. The jaw members are movable relative to one another from a first position wherein the jaw members are disposed in spaced relation relative to one another to a second position wherein the jaw members cooperate to grasp tissue therebetween. A source of electrosurgical energy is connected to at least one of the jaw members such that the jaw members are capable of sealing tissue held therebetween.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.15/927,189, filed on Mar. 21, 2018, which is a continuation of U.S.patent application Ser. No. 14/719,564 filed on May 22, 2015, now U.S.Pat. No. 10,568,682, which is a continuation of U.S. patent applicationSer. No. 14/034,659 filed on Sep. 24, 2013, now U.S. Pat. No. 9,737,357,which is a continuation of U.S. patent application Ser. No. 11/827,297filed on Jul. 11, 2007, now U.S. Pat. No. 8,540,711, which is acontinuation of U.S. patent application Ser. No. 11/513,979 filed onAug. 31, 2006, now U.S. Pat. No. 7,255,697, which is a continuation ofU.S. patent application Ser. No. 10/179,863 filed on Jun. 25, 2002, nowU.S. Pat. No. 7,101,371, which is a continuation-in-part of U.S. patentapplication Ser. No. 10/116,944 filed on Apr. 5, 2002, now U.S. Pat. No.7,083,618, which is a continuation-in-part of PCT Application No.PCT/US02/01890 filed on Jan. 22, 2002, which is a continuation-in-partof PCT Application No. PCT/US01/11340 filed on Apr. 6, 2001, the entirecontents of each of which are incorporated herein by reference.

BACKGROUND

The present disclosure relates to an electrosurgical instrument andmethod for performing endoscopic surgical procedures and moreparticularly, the present disclosure relates to an open or endoscopicbipolar electrosurgical forceps and method for sealing and/or cuttingtissue.

TECHNICAL FIELD

A hemostat or forceps is a simple plier-like tool which uses mechanicalaction between its jaws to constrict vessels and is commonly used inopen surgical procedures to grasp, dissect and/or clamp tissue.Electrosurgical forceps utilize both mechanical clamping action andelectrical energy to effect hemostasis by heating the tissue and bloodvessels to coagulate, cauterize and/or seal tissue.

Over the last several decades, more and more surgeons are complimentingtraditional open methods of gaining access to vital organs and bodycavities with endoscopes and endoscopic instruments which access organsthrough small puncture-like incisions. Endoscopic instruments areinserted into the patient through a cannula, or port, that has been madewith a trocar. Typical sizes for cannulas range from three millimetersto twelve millimeters. Smaller cannulas are usually preferred, which, ascan be appreciated, ultimately presents a design challenge to instrumentmanufacturers who must find ways to make surgical instruments that fitthrough the cannulas.

Certain endoscopic surgical procedures require cutting blood vessels orvascular tissue. However, due to space limitations surgeons can havedifficulty suturing vessels or performing other traditional methods ofcontrolling bleeding, e.g., clamping and/or tying-off transected bloodvessels. Blood vessels, in the range below two millimeters in diameter,can often be closed using standard electrosurgical techniques. However,if a larger vessel is severed, it may be necessary for the surgeon toconvert the endoscopic procedure into an open-surgical procedure andthereby abandon the benefits of laparoscopy.

Several journal articles have disclosed methods for sealing small bloodvessels using electrosurgery. An article entitled Studies on Coagulationand the Development of an Automatic Computerized Bipolar Coagulator, J.Neurosurg., Volume 75, July 1991, describes a bipolar coagulator whichis used to seal small blood vessels. The article states that it is notpossible to safely coagulate arteries with a diameter larger than 2 to2.5 mm. A second article is entitled Automatically Controlled BipolarElectrocoagulation—“COA-COMP”, Neurosurg. Rev. (1984), pp. 187-190,describes a method for terminating electrosurgical power to the vesselso that charring of the vessel walls can be avoided.

As mentioned above, by utilizing an electrosurgical forceps, a surgeoncan either cauterize, coagulate/desiccate and/or simply reduce or slowbleeding, by controlling the intensity, frequency and duration of theelectrosurgical energy applied through the jaw members to the tissue.The electrode of each jaw member is charged to a different electricpotential such that when the jaw members grasp tissue, electrical energycan be selectively transferred through the tissue.

In order to effect a proper seal with larger vessels, two predominantmechanical parameters must be accurately controlled—the pressure appliedto the vessel and the gap distance between the electrodes—both of whichare affected by the thickness of the sealed vessel. More particularly,accurate application of pressure is important to oppose the walls of thevessel; to reduce the tissue impedance to a low enough value that allowsenough electrosurgical energy through the tissue; to overcome the forcesof expansion during tissue heating; and to contribute to the end tissuethickness which is an indication of a good seal. It has been determinedthat a typical fused vessel wall is optimum between 0.001 and 0.005inches. Below this range, the seal may shred or tear and above thisrange the lumens may not be properly or effectively sealed.

With respect to smaller vessel, the pressure applied to the tissue tendsto become less relevant whereas the gap distance between theelectrically conductive surfaces becomes more significant for effectivesealing. In other words, the chances of the two electrically conductivesurfaces touching during activation increases as the vessels becomesmaller.

Electrosurgical methods may be able to seal larger vessels using anappropriate electrosurgical power curve, coupled with an instrumentcapable of applying a large closure force to the vessel walls. It isthought that the process of coagulating small vessels is fundamentallydifferent than electrosurgical vessel sealing. For the purposes herein,“coagulation” is defined as a process of desiccating tissue wherein thetissue cells are ruptured and dried. Vessel sealing is defined as theprocess of liquefying the collagen in the tissue so that it reforms intoa fused mass. Thus, coagulation of small vessels is sufficient topermanently close them. Larger vessels need to be sealed to assurepermanent closure.

U.S. Pat. No. 2,176,479 to Willis, U.S. Pat. Nos. 4,005,714 and4,031,898 to Hiltebrandt, U.S. Pat. Nos. 5,827,274, 5,290,287 and5,312,433 to Boebel et al., U.S. Pat. Nos. 4,370,980, 4,552,143,5,026,370 and 5,116,332 to Lottick, U.S. Pat. No. 5,443,463 to Stern etal., U.S. Pat. No. 5,484,436 to Eggers et al. and U.S. Pat. No.5,951,549 to Richardson et al., all relate to electrosurgicalinstruments for coagulating, cutting and/or sealing vessels or tissue.However, some of these designs may not provide uniformly reproduciblepressure to the blood vessel and may result in an ineffective ornon-uniform seal.

Many of these instruments include blade members or shearing memberswhich simply cut tissue in a mechanical and/or electromechanical mannerand are relatively ineffective for vessel sealing purposes. Otherinstruments rely on clamping pressure alone to procure proper sealingthickness and are not designed to take into account gap tolerancesand/or parallelism and flatness requirements which are parameters which,if properly controlled, can assure a consistent and effective tissueseal. For example, it is known that it is difficult to adequatelycontrol thickness of the resulting sealed tissue by controlling clampingpressure alone for either of two reasons: 1) if too much force isapplied, there is a possibility that the two poles will touch and energywill not be transferred through the tissue resulting in an ineffectiveseal; or 2) if too low a force is applied the tissue may pre-maturelymove prior to activation and sealing and/or a thicker, less reliableseal may be created.

As mentioned above, in order to properly and effectively seal largervessels, a greater closure force between opposing jaw members isrequired. It is known that a large closure force between the jawstypically requires a large moment about the pivot for each jaw. Thispresents a challenge because the jaw members are typically affixed withpins which are positioned to have a small moment arms with respect tothe pivot of each jaw member. A large force, coupled with a small momentarm, is undesirable because the large forces may shear the pins. As aresult, designers must compensate for these large closure forces byeither designing instruments with metal pins and/or by designinginstruments which at least partially offload these closure forces toreduce the chances of mechanical failure. As can be appreciated, ifmetal pivot pins are employed, the metal pins must be insulated to avoidthe pin acting as an alternate current path between the jaw memberswhich may prove detrimental to effective sealing.

Increasing the closure forces between electrodes may have otherundesirable effects, e.g., it may cause the opposing electrodes to comeinto close contact with one another which may result in a short circuitand a small closure force may cause pre-mature movement of the issueduring compression and prior to activation.

Typically and particularly with respect to endoscopic electrosurgicalprocedures, once a vessel is sealed, the surgeon has to remove thesealing instrument from the operative site, substitute a new instrumentthrough the cannula and accurately sever the vessel along the newlyformed tissue seal. As can be appreciated, this additional step may beboth time consuming (particularly when sealing a significant number ofvessels) and may contribute to imprecise separation of the tissue alongthe sealing line due to the misalignment or misplacement of the severinginstrument along the center of the tissue sealing line.

Several attempts have been made to design an instrument whichincorporates a knife or blade member which effectively severs the tissueafter forming a tissue seal. For example, U.S. Pat. No. 5,674,220 to Foxet al. discloses a transparent vessel sealing instrument which includesa longitudinally reciprocating knife which severs the tissue oncesealed. The instrument includes a plurality of openings which enabledirect visualization of the tissue during the sealing and severingprocess. This direct visualization allows a user to visually andmanually regulate the closure force and gap distance between jaw membersto reduce and/or limit certain undesirable visual effects known to occurwhen sealing vessels, thermal spread, charring, etc. As can beappreciated, the overall success of creating an effective tissue sealwith this instrument is greatly reliant upon the user's expertise,vision, dexterity, and experience in judging the appropriate closureforce, gap distance and length of reciprocation of the knife touniformly, consistently and effectively seal the vessel and separate thetissue at the seal along an ideal cutting plane.

U.S. Pat. No. 5,702,390 to Austin et al. discloses a vessel sealinginstrument which includes a triangularly-shaped electrode which isrotatable from a first position to seal tissue to a second position tocut tissue. Again, the user must rely on direct visualization andexpertise to control the various effects of sealing and cutting tissue.

Thus, a need exists to develop an electrosurgical instrument whicheffectively and consistently seals and separates vascular tissue andsolves many of the aforementioned problems known in the art.

SUMMARY

The present disclosure relates to an endoscopic bipolar forceps includesan elongated shaft having opposing jaw members at a distal end thereof.The jaw members are movable relative to one another from a firstposition wherein the jaw members are disposed in spaced relationrelative to one another to a second position wherein the jaw memberscooperate to grasp tissue therebetween. The forceps also includes asource of electrical energy connected to each jaw member such that thejaw members are capable of conducting energy through tissue heldtherebetween to effect a seal. A generally tube-like cutter is includedwhich is slidably engaged about the elongated shaft and which isselectively movable about the elongated shaft to engage and cut tissueon at least one side of the jaw members while the tissue is engagedbetween jaw members.

Preferably, the cutter includes a U-shaped notched blade and the bladeis recessed from the outer periphery of the cutter. In one embodiment,the blade includes a bevel having opposing sharp edges disposed withinthe proximal most portion of the U-shaped blade. In another embodiment,the U-shaped blade includes opposing serrated edges to facilitatesevering the tissue. Alternatively, the U-shaped notch can includeopposing substantially dull edges and the cutter is rapidly advancedthrough the tissue under a spring pressure, hydraulic pressure,electrical actuator or the like.

In another embodiment, the cutter includes a remotely operable actuatorfor selectively deploying the cutter to sever tissue. Preferably, theactuator is a trigger. In yet another embodiment, the cutter rotates asthe cutter severs tissue on at least one side of the jaw members whilethe tissue is engaged between jaw members.

The cutter may be designed to mechanically cut tissue,electromechanically cut tissue (i.e., RF energy, ultrasonic energy)and/or thermo-mechanically cut tissue depending upon a particularpurpose. In one particular embodiment, the cutter is connected to asource of electrosurgical energy and the cutter severs tissue in amechanical and electrosurgical manner.

Preferably, the cutter includes a cutting area having a U-shaped notchedblade at a proximal end thereof and a pair of arms at a distal endthereof. The arms are dimensioned to feed tissue into the cutting areainto contact with the U-shaped notched blade upon distal movement of thecutter.

Another embodiment of the present invention includes an elongated shafthaving opposing jaw members at a distal end thereof. One of the jawmembers is movable relative to the other jaw member from a firstposition wherein the jaw members are disposed in spaced relationrelative to one another to a second position wherein the jaw memberscooperate to grasp tissue therebetween. An electrically conductive outersleeve is included which at least partially surrounds the shaft. Theouter sleeve mechanically cooperates with the movable jaw member topivot the movable jaw member from the first to second positions. Theforceps also includes an actuator for selectively moving the outersleeve to electrosurgically energize and pivot the jaw members. The jawmembers may be closed and energized simultaneously or independently bythe actuator.

In one embodiment, the movable jaw member includes a protrusion whichmechanically interfaces with the outer sleeve such that when the sleevemoves in a first direction, the movable jaw member pivots to the firstposition and is electrically isolated from the outer sleeve. Moreover,when the sleeve moves in a second direction, the movable jaw memberpivots into the second position and the outer sleeve electrosurgicallyenergizes the movable jaw member.

Preferably, at least one of the jaw members includes a knife channel forreciprocating a knife therethrough and the distal end of the elongatedshaft houses the knife within a corresponding knife cavity. The knife isprevented from reciprocating through the knife channel when the jawmember is in the first position and the knife channel and the knifecavity are out of alignment.

Preferably, the jaw members include opposing conductive sealing surfacesdisposed on the inner facing surfaces of the jaw members and at leastone of the jaw members is made from a hard anodized aluminum having highdielectric properties. Each jaw member includes an outer peripheralsurface coated with a material which reduces tissue adherence. Thecoating is selected from a group of materials consisting of: TiN, ZrN,TiAlN, CrN, Ni200, Ni201, inconel 600, and resinous fluorine containingpolymers or polytetrafluoroethylene.

BRIEF DESCRIPTION OF THE DRAWINGS

Various embodiments of the subject instrument are described herein withreference to the drawings wherein:

FIG. 1A is a left, perspective view of an endoscopic bipolar forcepsshowing a housing, a shaft and an end effector assembly according to thepresent disclosure;

FIG. 1B is a left, perspective of an open bipolar forceps according tothe present disclosure;

FIG. 2 is a top view of the forceps of FIG. 1;

FIG. 3 is a right, side view of the forceps of FIG. 1;

FIG. 4 is a right, perspective view of the forceps of FIG. 1 showing therotation of the end effector assembly about a longitudinal axis “A”;

FIG. 5 is a front view of the forceps of FIG. 1;

FIG. 6 is an enlarged view of the indicated area of detail of FIG. 5showing an enhanced view of the end effector assembly detailing a pairof opposing jaw members;

FIG. 7 is an enlarged, left perspective view of the indicated area ofdetail of FIG. 1 showing another enhanced view of the end effectorassembly;

FIG. 8 is an enlarged, right side view of the indicated area of detailof FIG. 3 with a pair of cam slots of the end effector assembly shown inphantom;

FIG. 9 is a slightly-enlarged, cross-section of the forceps of FIG. 3showing the internal working components of the housing;

FIG. 10 is an enlarged, cross-section of the indicated area of detail ofFIG. 9 showing the initial position of a knife assembly disposed withinthe end effector assembly;

FIG. 11 is an enlarged, left perspective view showing the housingwithout a cover plate and the internal working components of the forcepsdisposed therein;

FIG. 12 is an exploded, perspective view of the end effector assembly,the knife assembly and the shaft;

FIG. 13 is an exploded, perspective view of the housing and the internalworking components thereof with the attachment of the shaft and endeffector assembly to the housing shown in broken line illustration;

FIG. 14 is greatly-enlarged, top perspective view of the end effectorassembly with parts separated showing a feed path for an electricalcable through the top jaw member;

FIG. 15 is a longitudinal, cross-section of the indicated area of detailof FIG. 9;

FIG. 16 is an enlarged, top perspective view of the end effectorassembly showing the feed path for the electrical cable through theopposing jaw members and the proximal attachment of the knife assemblyto a longitudinally-reciprocating knife tube disposed within the shaft;

FIG. 17 is an enlarged, top perspective view of the end effectorassembly showing the feed path for the electrical cable along alongitudinally-disposed channel defined within the outer periphery ofthe shaft;

FIG. 18A is a greatly-enlarged, side perspective view of the housingwithout the cover plate showing the feed path for the electrical cablethrough a rotating assembly adjacent to a distal end of the housing;

FIG. 18B is a greatly-enlarged, side perspective view of the housingwithout the cover plate showing the feed path for the electrical cablethrough a rotating assembly with the shaft mounted within the housing;

FIG. 19 is a greatly-enlarged, rear view of the rotating assemblyshowing an internally-disposed stop member;

FIG. 20 is a perspective view of the forceps of the present disclosureshown in position to grasp and seal a tubular vessel or bundle through acannula;

FIG. 21 is a slightly-enlarged, cross-section of the internal,cooperative movements of a four-bar handle assembly disposed within thehousing which effects movement of the jaw members relative to oneanother;

FIG. 22 is a greatly-enlarged, cross-section showing the initialmovement of a flange upon activation of the four-bar handle assemblyshown in phantom illustration;

FIG. 23 is a greatly-enlarged, side view showing the resultingcompression movement of a coil spring in reaction to the movement of thefour-bar handle assembly;

FIG. 24 is a greatly-enlarged, side view showing the proximal movementof a cam-like drive pin of the end effector assembly as a result of theproximal compression of the coil spring of FIG. 23 which, in turn, movesthe opposing jaw members into a closed configuration;

FIG. 25 is a greatly-enlarged, cross-section showing the knife assemblypoised for activation within a cannula;

FIG. 26 is a top perspective view showing the opposing jaw members inclosed configuration with a tubular vessel compressed therebetween;

FIG. 27 is an enlarged perspective view of a sealed site of a tubularvessel showing a preferred cutting line “B-B” for dividing the tubularvessel after sealing;

FIG. 28 is a longitudinal cross-section of the sealed site taken alongline 28-28 of FIG. 27;

FIG. 29 is a side view of the housing without a cover plate showing thelongitudinal reciprocation of the knife tube upon activation of atrigger assembly;

FIG. 30 is a greatly-enlarged, cross-section of the distal end of theinstrument showing longitudinal reciprocation of the knife assembly uponactivation of the trigger assembly;

FIG. 31 is a longitudinal cross-section of the tubular vessel afterreciprocation of the knife assembly through the sealing site alongpreferred cutting line “B-B” of FIG. 28;

FIG. 32 is a greatly-enlarged, side view showing movement of the flangeupon re-initiation of the handle assembly along a predefined exit pathwhich, in turn, opens the opposing jaw members and releases the tubularvessel;

FIG. 33 is a greatly enlarged, perspective view showing one particularstop member configuration on one of the vessel sealing surfaces of oneof the jaw members;

FIG. 34A is an internal side view of the housing showing one embodimentof a handswitch for use with the present disclosure;

FIG. 34B is a schematic illustration of an alternate embodiment of thehandswitch according to the present disclosure; and

FIG. 34C is a schematic illustration of another embodiment of thehandswitch according to the present disclosure;

FIGS. 35A and 35B are schematic illustrations of heating blocksaccording to the present disclosure;

FIGS. 35C and 35D are schematic illustrations jaw members withintermittent sealing surface patterns;

FIG. 36 shows one embodiment of a slide tube cutter in accordance withthe present invention;

FIG. 37A shows one embodiment of a laparoscopic forceps with the slidetube cutter of FIG. 36 wherein the slide tube cutter is poised forlongitudinal reciprocation of U-shaped notched blade through a vesselalong a seal plane “B-B”;

FIG. 37B shows another embodiment of a laparoscopic forceps with theslide tube cutter of FIG. 36 wherein the slide tube cutter is poised forlongitudinal reciprocation and rotation of U-shaped notched bladethrough a vessel along a seal plane “B-B”;

FIGS. 38A and 38B show tow alternate embodiments of the slide tubecutter in accordance with the present disclosure;

FIG. 39A shows a laparoscopic forceps having a unilateral closuremechanism shown in open configuration;

FIG. 39B shows a laparoscopic forceps having a unilateral closuremechanism shown in closed configuration;

FIG. 39C shows a laparoscopic forceps having a unilateral closuremechanism shown in open configuration with a knife blade andcorresponding knife channel shown in phantom;

FIG. 39D shows a laparoscopic forceps having a unilateral closuremechanism shown in closed configuration with a knife blade andcorresponding knife channel shown in phantom; and

FIG. 40 is an enlarged, cross-section of the end effector assemblyshowing a hot wire poised for selective reciprocation to cut tissue.

DETAILED DESCRIPTION

Referring now to FIGS. 1-6, one embodiment of a bipolar forceps 10 isshown for use with various surgical procedures and generally includes ahousing 20, a handle assembly 30, a rotating assembly 80, a triggerassembly 70 and an end effector assembly 100 which mutually cooperate tograsp, seal and divide tubular vessels and vascular tissue 420 (FIG.20). Although the majority of the figure drawings depict a bipolarforceps 10 for use in connection with endoscopic surgical procedures, anopen forceps 10′ is also contemplated for use in connection withtraditional open surgical procedures and is shown by way of example inFIG. 1A. For the purposes herein, the endoscopic version is discussed indetail, however, it is contemplated that open forceps 10′ also includesthe same or similar operating components and features as describedbelow.

More particularly, forceps 10 includes a shaft 12 which has a distal end14 dimensioned to mechanically engage the end effector assembly 100 anda proximal end 16 which mechanically engages the housing 20. Preferably,shaft 12 is bifurcated at the distal end 14 thereof to form ends 14 aand 14 b which are dimensioned to receive the end effector assembly 100as best seen in FIGS. 7 and 12. The proximal end 16 of shaft 12 includesnotches 17 a (See FIGS. 23 and 29) and 17 b (See FIGS. 11, 12 and 13)which are dimensioned to mechanically engage corresponding detents 83 a(FIG. 18A) and 83 b (FIG. 13 shown in phantom) of rotating assembly 80as described in more detail below. In the drawings and in thedescriptions which follow, the term “proximal”, as is traditional, willrefer to the end of the forceps 10 which is closer to the user, whilethe term “distal” will refer to the end which is further from the user.

As best seen in FIG. 1A, forceps 10 also includes an electricalinterface or plug 300 which connects the forceps 10 to a source ofelectrosurgical energy, e.g., a generator (not shown). Plug 300 includesa pair of prong members 302 a and 302 b which are dimensioned tomechanically and electrically connect the forceps 10 to the source ofelectrosurgical energy. An electrical cable 310 extends from the plug300 to a sleeve 99 which securely connects the cable 310 to the forceps10. As best seen in FIGS. 9, 11 and 18A, cable 310 is internally dividedinto cable lead 310 a and 310 b which each transmit electrosurgicalenergy through their respective feed paths through the forceps 10 to theend effector assembly 100 as explained in more detail below.

Handle assembly 30 includes a fixed handle 50 and a movable handle 40.Fixed handle 50 is integrally associated with housing 20 and handle 40is movable relative to fixed handle 50 as explained in more detail belowwith respect to the operation of the forceps 10. Rotating assembly 80 ispreferably attached to a distal end 303 (FIG. 18A) of housing 20 and isrotatable approximately 180 degrees in either direction about alongitudinal axis “A”.

As best seen in FIGS. 2 and 13, housing 20 is formed from two (2)housing halves 20 a and 20 b which each include a plurality ofinterfaces 307 a, 307 b and 307 c (FIG. 13) which are dimensioned tomechanically align and engage one another to form housing 20 and enclosethe internal working components of forceps 10. As can be appreciated,fixed handle 50 which, as mentioned above is integrally associated withhousing 20, takes shape upon the assembly of the housing halves 20 a and20 b.

It is envisioned that a plurality of additional interfaces (not shown)may disposed at various points around the periphery of housing halves 20a and 20 b for ultrasonic welding purposes, e.g., energydirection/deflection points. It is also contemplated that housing halves20 a and 20 b (as well as the other components described below) may beassembled together in any fashion known in the art. For example,alignment pins, snap-like interfaces, tongue and groove interfaces,locking tabs, adhesive ports, etc. may all be utilized either alone orin combination for assembly purposes.

Likewise, rotating assembly 80 includes two halves 80 a and 80 b which,when assembled, enclose and engage the proximal end 16 of shaft 12 topermit selective rotation of the end effector assembly 100 as needed.Half 80 a includes a pair of detents 89 a (FIG. 13) which aredimensioned to engage a pair of corresponding sockets 89 b (shown inphantom in FIG. 13) disposed within half 80 b. Movable handle 40 andtrigger assembly 70 are preferably of unitary construction and areoperatively connected to the housing 20 and the fixed handle 50 duringthe assembly process.

As mentioned above, end effector assembly 100 is attached to the distalend 14 of shaft 12 and includes a pair of opposing jaw members 110 and120. Movable handle 40 of handle assembly 30 is ultimately connected toa drive rod 32 which, together, mechanically cooperate to impartmovement of the jaw members 110 and 120 from an open position whereinthe jaw members 110 and 120 are disposed in spaced relation relative toone another, to a clamping or closed position wherein the jaw members110 and 120 cooperate to grasp tissue 420 (FIG. 20) therebetween. Thisis explained in more detail below with respect to FIGS. 9-11 and 20-29.

It is envisioned that the forceps 10 may be designed such that it isfully or partially disposable depending upon a particular purpose or toachieve a particular result. For example, end effector assembly 100 maybe selectively and releasably engageable with the distal end 14 of theshaft 12 and/or the proximal end 16 of shaft 12 may be selectively andreleasably engageable with the housing 20 and the handle assembly 30. Ineither of these two instances, the forceps 10 would be considered“partially disposable” or “reposable”, i.e., a new or different endeffector assembly 100 (or end effector assembly 100 and shaft 12)selectively replaces the old end effector assembly 100 as needed.

Turning now to the more detailed features of the present disclosure asdescribed with respect to FIGS. 1A-13, movable handle 40 includes anaperture 42 defined therethrough which enables a user to grasp and movethe handle 40 relative to the fixed handle 50. Handle 40 also includesan ergonomically-enhanced gripping element 45 disposed along the innerperipheral edge of aperture 42 which is designed to facilitate grippingof the movable handle 40 during activation. It is envisioned thatgripping element 45 may include one or more protuberances, scallopsand/or ribs 43 a, 43 b and 43 c, respectively, to facilitate gripping ofhandle 40. As best seen in FIG. 11, movable handle 40 is selectivelymoveable about a pivot 69 from a first position relative to fixed handle50 to a second position in closer proximity to the fixed handle 50which, as explained below, imparts movement of the jaw members 110 and120 relative to one another.

As shown best in FIG. 11, housing 20 encloses a drive assembly 21 whichcooperates with the movable handle 40 to impart movement of the jawmembers 110 and 120 from an open position wherein the jaw members 110and 120 are disposed in spaced relation relative to one another, to aclamping or closed position wherein the jaw members 110 and 120cooperate to grasp tissue therebetween. The handle assembly 30 cangenerally be characterized as a four-bar mechanical linkage composed ofthe following elements: movable handle 40, a link 65, a cam-like link 36and a base link embodied by fixed handle 50 and a pair of pivot points37 and 67 b. Movement of the handle 40 activates the four-bar linkagewhich, in turn, actuates the drive assembly 21 for imparting movement ofthe opposing jaw members 110 and 120 relative to one another to grasptissue therebetween. It is envisioned that employing a four-barmechanical linkage will enable the user to gain a significant mechanicaladvantage when compressing the jaw members 110 and 120 against thetissue 420 as explained in further detail below with respect theoperating parameters of the drive assembly 21. Although shown as afour-bar mechanical linkage, the present disclosure contemplates otherlinkages to effect relative motion of the jaw members 110 and 120 as isknown in the art.

Preferably, fixed handle 50 includes a channel 54 defined therein whichis dimensioned to receive a flange 92 which extends proximally frommovable handle 40. Preferably, flange 92 includes a fixed end 90 whichis affixed to movable handle 40 and a t-shaped free end 93 which isdimensioned for facile reception within channel 54 of handle 50. It isenvisioned that flange 92 may be dimensioned to allow a user toselectively, progressively and/or incrementally move jaw members 110 and120 relative to one another from the open to closed positions. Forexample, it is also contemplated that flange 92 may include aratchet-like interface which lockingly engages the movable handle 40and, therefore, jaw members 110 and 120 at selective, incrementalpositions relative to one another depending upon a particular purpose.Other mechanisms may also be employed to control and/or limit themovement of handle 40 relative to handle 50 (and jaw members 110 and120) such as, e.g., hydraulic, semi-hydraulic, linear actuator(s),gas-assisted mechanisms and/or gearing systems.

As best illustrated in FIG. 11, housing halves 20 a and 20 b of housing20, when assembled, form an internal cavity 52 which predefines thechannel 54 within fixed handle 50 such that an entrance pathway 53 andan exit pathway 58 are formed for reciprocation of the t-shaped flangeend 93 therein. Once assembled, two generally triangular-shaped members57 a and 57 b are positioned in close abutment relative to one anotherto define a rail or track 59 therebetween. During movement of the flange92 along the entrance and exit pathways 53 and 58, respectively, thet-shaped end 93 rides along track 59 between the two triangular members57 a and 57 b according to the particular dimensions of thetriangularly-shaped members 57 a and 57 b, which, as can be appreciated,predetermines part of the overall pivoting motion of handle 40 relativeto fixed handle 50.

Once actuated, handle 40 moves in a generally arcuate fashion towardsfixed handle 50 about pivot 69 which causes link 65 to rotate proximallyabout pivots 67 a and 67 b which, in turn, cause cam-like link 36 torotate about pivots 37 and 69 in a generally proximal direction.Movement of the cam-like link 36 imparts movement to the drive assembly21 as explained in more detail below. Moreover, proximal rotation of thelink 65 about pivots 67 a and 67 b also causes a distal end 63 of link65 to release, i.e., “unlock”, the trigger assembly 70 for selectiveactuation. This feature is explained in detail with reference to FIGS.21-29 and the operation of the knife assembly 200.

Turning now to FIG. 12 which shows an exploded view of the shaft 12 andend effector assembly 100. As mentioned above, shaft 12 includes distaland proximal ends 14 and 16, respectively. The distal end 14 isbifurcated and includes ends 14 a and 14 b which, together, define acavity 18 for receiving the end effector assembly 100. The proximal end16 includes a pair of notches 17 a (FIG. 29) and 17 b (FIG. 11) whichare dimensioned to engage corresponding detents 83 a and 83 b (FIG. 13)of the rotating assembly 80. As can be appreciated, actuation of therotation assembly 80 rotates the shaft 12 which, in turn, rotates theend effector assembly 100 to manipulate and grasp tissue 420.

Shaft 12 also includes a pair of longitudinally-oriented channels 19 a(FIG. 15) and 19 b (FIG. 12) which are each dimensioned to carry anelectrosurgical cable lead 310 a and 310 b, respectively, therein forultimate connection to each jaw member 120 and 110, respectively, asexplained in more detail with reference to FIGS. 14-17 below. Shaft 12also includes a pair of longitudinally oriented slots 197 a and 197 bdisposed on ends 14 a and 14 b, respectively. Slots 197 a and 197 b arepreferable dimensioned to allow longitudinal reciprocation of a cam pin170 therein which, as explained below with reference to FIGS. 23 and 24,causes movement of the opposing jaw member 110 and 120 from the open toclosed positions.

Shaft 12 also includes a pair of sockets 169 a and 169 b disposed atdistal ends 14 a and 14 b which are dimensioned to receive acorresponding pivot pin 160. As explained below, pivot pin 160 securesjaws 110 and 120 to the shaft 12 between bifurcated distal ends 14 a and14 b and mounts the jaw members 110 and 120 such that longitudinalreciprocation of the cam pin 170 rotates jaw members 110 and 120 aboutpivot pin 160 from the open to closed positions.

Shaft 12 is preferably dimensioned to slidingly receive a knife tube 34therein which engages the knife assembly 200 such that longitudinalmovement of the knife tube 34 actuates the knife assembly 200 to dividetissue 420 as explained below with respect to FIGS. 29-31. Knife tube 34includes a rim 35 located at a proximal end thereof and a pair ofopposing notches 230 a and 230 b (FIGS. 25 and 30) located at a distalend 229 thereof. As best shown in FIG. 13, rim 35 is dimensioned toengage a corresponding sleeve 78 disposed at a distal end of the triggerassembly 70 such that distal movement of the sleeve 78 translates theknife tube 34 which, in turn, actuates the knife assembly 200. A seal193 may be mounted atop the knife tube 34 and positioned between theknife tube 34 and the shaft 12. It is envisioned that the seal 193 maybe dimensioned to facilitate reciprocation of the knife tube 34 withinthe shaft 12 and/or to protect the other, more sensitive, internaloperating components of the forceps from undesirable fluid inundationduring surgery. Seal 193 may also be employed to control/regulatepneumo-peritoneal pressure leakage through forceps 10 during surgery.Seal 193 preferably includes a pair of opposing bushings 195 a and 195 bwhich assure consistent and accurate reciprocation of the knife tube 34within shaft 12 (See FIG. 15).

Notches 230 a and 230 b are preferably dimensioned to engage acorresponding key-like interface 211 of the knife assembly 200 whichincludes a pair of opposing detents 212 a and 212 b and a pair ofopposing steps 214 a and 214 b. As best illustrated in FIGS. 25 and 30,each detent and step arrangement, e.g., 212 a and 214 a, respectively,securely engages a corresponding notch, e.g., 230 a, such that thedistal end of the step 214 a abuts the distal end 229 of the knife tube34. It is envisioned that engaging the knife tube 34 to the knifeassembly 200 in this manner will assure consistent and accurate distaltranslation of the knife tube 34 through the tissue 420.

As can be appreciated from the present disclosure, the knife tube 34 andknife assembly 200 are preferably assembled to operate independentlyfrom the operation of the drive assembly 21. However and as described inmore detail below, knife assembly 200 is dependent on the drive assembly21 for activation purposes, i.e., the activation/movement of the driveassembly 21 (via handle assembly 30 and the internal working componentsthereof) “unlocks” the knife assembly 200 for selective, separation ofthe tissue. For the purposes herein, the drive assembly 21 consists ofboth the drive rod 32 and the compression mechanism 24 which includes anumber of cooperative elements which are described below with referenceto FIG. 13. It is envisioned that arranging the drive assembly 21 inthis fashion will enable facile, selective engagement of the drive rod32 within the compression mechanism 24 for assembly purposes.

Although the drawings depict a disposable version of the presentlydisclosed forceps 10, it is contemplated that the housing 20 may includea release mechanism (not shown) which enables selectively replacement ofthe drive rod 32 for disposal purposes. In this fashion, the forcepswill be considered “partially disposable” or “reposable”, i.e., theshaft 12, end effector assembly 100 and knife assembly 200 aredisposable and/or replaceable whereas the housing 20 and handle assembly30 are re-usable.

As best illustrated in FIGS. 16 and 17, drive rod 32 includes a pair ofchamfered or beveled edges 31 a and 31 b at a distal end thereof whichare preferably dimensioned to allow facile reciprocation of the driverod 32 through a knife carrier or guide 220 which forms a part of theknife assembly 200. A pin slot 39 is disposed at the distal tip of thedrive rod 32 and is dimensioned to house the cam pin 170 such thatlongitudinal reciprocation of the drive rod 32 within the knife tube 34translates the cam pin 170, which, in turn, rotates the jaw members 110and 120 about pivot pin 160. As will be explained in more detail belowwith respect to FIGS. 23 and 24, the cam pin 170 rides within slots 172and 174 of the jaw members 110 and 120, respectively, which causes thejaw members 110 and 120 to rotate from the open to closed positionsabout the tissue 420.

The proximal end of the drive rod 32 includes a tab 33 which ispreferably dimensioned to engage a corresponding compression sleeve 28disposed within the compression mechanism 24. Proximal movement of thesleeve 28 (as explained below with respect to FIGS. 21-24) reciprocates(i.e., pulls) the drive rod 32 which, in turn, pivots the jaw members110 and 120 from the open to closed positions. Drive rod 32 alsoincludes a donut-like spacer or o-ring 95 which is dimensioned tomaintain pneumo-peritoneal pressure during endoscopic procedures. It isalso envisioned that o-ring 95 may also prevent the inundation ofsurgical fluids which may prove detrimental to the internal operatingcomponents of the forceps 10. O-ring 95 is made also be made from amaterial having a low coefficient of friction to facilitate uniform andaccurate reciprocation of the drive rod 32 within the knife tube 34.

As mentioned above, the knife assembly 200 is disposed between opposingjaw members 110 and 120 of the end effector assembly 100. Preferably,the knife assembly 200 and the end effector assembly 100 areindependently operable, i.e., the trigger assembly 70 actuates the knifeassembly 200 and the handle assembly 30 actuates the end effectorassembly 100. Knife assembly 200 includes a bifurcated knife bar or rod210 having two forks 210 a and 210 b and a knife carrier or guide 220.Knife forks 210 a and 210 b include the above-described key-likeinterfaces 211 (composed of steps 214 a, 214 b and detents 212 a, 212 b,respectively) disposed at the proximal end thereof for engaging theknife tube 34 (as described above) and a common distal end 206 whichcarries a blade 205 thereon for severing tissue 420. Preferably, eachfork 210 a and 210 b includes a taper 213 a and 213 b, respectively,which converge to form common distal end 206. It is envisioned that thetapers 213 a and 213 b facilitate reciprocation of the knife blade 205through the end effector assembly 100 as described in more detail belowand as best illustrated in FIG. 30.

Each fork 210 a and 210 b also includes a tapered shoulder portion 221 aand 221 b disposed along the outer periphery thereof which isdimensioned to engage a corresponding slot 223 a and 223 b,respectively, disposed in the knife carrier or guide 220 (See FIG. 16).It is envisioned that this shoulder portion 221 a, 221 b and slot 223 a,223 b arrangement may be designed to restrict and/or regulate theoverall distal movement of the blade 205 after activation. Each fork 210a and 210 b also includes an arcuately-shaped notch 215 a and 215 b,respectively disposed along the inward edge thereof which is dimensionedto facilitate insertion of a roller or bushing 216 disposed between thejaw members 110 and 120 during assembly.

As mentioned above, knife assembly 200 also includes a knife carrier orguide 220 which includes opposing spring tabs 222 a and 222 b at aproximal end thereof and upper and lower knife guides 224 a and 224 b,respectively, at the distal end thereof. The inner facing surface ofeach spring tab, e.g., 222 b, is preferably dimensioned to matinglyengage a corresponding chamfered edge, e.g., 31 b of the drive rod 32(FIG. 16) and the outer facing surface is preferably dimensioned forfriction-fit engagement with the inner periphery of the shaft 12. Asbest seen in FIG. 12, knife carrier 220 also includes a drive rodchannel 225 defined therethrough which is dimensioned to allowreciprocation of the drive rod 32 during the opening and closing of thejaw members 110 and 120. Knife guide 220 also includes rests 226 a and226 b which extend laterally therefrom which abut the proximal ends 132,134 of the jaw members 110 and 120 when disposed in the closed position.

Knife guides 224 a and 224 b preferably include slots 223 a and 223 b,respectively, located therein which guide the knife forks 210 a and 210b therealong during activation to provide consistent and accuratereciprocation of the knife blade 205 through the tissue 420. It isenvisioned that slots 223 a and 223 b also restrict undesirable lateralmovements of the knife assembly 200 during activation. Preferably, theknife carrier 220 is positioned at a point slightly beyond the shoulderportions 221 a and 221 b when assembled.

The knife assembly 200 also includes a roller or bushing 216 which isdimensioned to mate with the inner peripheral edge of each fork 210 aand 210 b such that, during activation, the forks 210 a and 210 b glideover the roller or bushing 216 to assure facile and accuratereciprocation of the knife assembly 200 through the tissue 420. Bushing216 is also dimensioned to seat between opposing jaw members 110 and 120and is preferably secured therebetween by pivot pin 160. As mentionedabove, the arcuately-shaped notches 215 a and 215 b facilitate insertionof the bushing 216 during assembly.

The end effector assembly 100 includes opposing jaw members 110 and 120which are seated within cavity 18 defined between bifurcated ends 14 aand 14 b of shaft 12. Jaw members 110 and 120 are generally symmetricaland include similar component features which cooperate to permit facilerotation about pivot pin 160 to effect the sealing and dividing oftissue 420. As a result and unless otherwise noted, only jaw member 110and the operative features associated therewith are describe in detailherein but as can be appreciated, many of these features apply to jawmember 120 as well.

More particularly, jaw member 110 includes a pivot flange 166 which hasan arcuately-shaped inner surface 167 which is dimensioned to allowrotation of jaw member 110 about bushing 216 and pivot pin 160 uponreciprocation of drive rod 32 as described above. Pivot flange 166 alsoincludes a cam slot 172 which is dimensioned to engage cam pin 170 suchthat longitudinal movement of the drive rod 32 causes the cam pin 170 toride along cam slot 172. It is envisioned that cam slot 172 may bedimensioned to allow different rotational paths depending upon aparticular purpose or to achieve a particular result. For example,commonly assigned, co-pending U.S. application Ser. No. 09/177,950 whichis hereby incorporated by reference in its entirety herein, describes atwo-stage cam slot arrangement which, as can be appreciated, provides aunique rotational path for the jaw members about the pivot point.

Pivot flange 166 also includes a recess 165 which is preferablydimensioned to secure one free end of the bushing 216 between jawmembers 110 and 120. The inner periphery of recess 165 is preferablydimensioned to receive pivot pin 160 therethrough to secure the jawmember 110 to the shaft 12. Jaw member 120 includes a similar recess 175(FIG. 14) which secures the opposite end of bushing 216 and jaw member120 to shaft 12.

Jaw member 110 also includes a jaw housing 116, an insulative substrateor insulator 114 and an electrically conducive surface 112. Jaw housing116 includes a groove (not shown—See groove 179 of jaw member 120)defined therein which is dimensioned to engage a ridge-like interface161 disposed along the outer periphery of insulator 114. Insulator 114is preferably dimensioned to securely engage the electrically conductivesealing surface 112. This may be accomplished by stamping, byovermolding, by overmolding a stamped electrically conductive sealingplate and/or by overmolding a metal injection molded seal plate.

All of these manufacturing techniques produce an electrode having anelectrically conductive surface 112 which is substantially surrounded byan insulating substrate 114. The insulator 114, electrically conductivesealing surface 112 and the outer, non-conductive jaw housing 116 arepreferably dimensioned to limit and/or reduce many of the knownundesirable effects related to tissue sealing, e.g., flashover, thermalspread and stray current dissipation. Alternatively, it is alsoenvisioned that the jaw members 110 and 120 may be manufactured from aceramic-like material and the electrically conductive surface(s) 112 arecoated onto the ceramic-like jaw members 110 and 120.

Preferably, the electrically conductive sealing surface 112 may alsoinclude a pinch trim 119 (FIG. 25) which facilitates secure engagementof the electrically conductive surface 112 to the insulating substrate114 and also simplifies the overall manufacturing process. It isenvisioned that the electrically conductive sealing surface 112 may alsoinclude an outer peripheral edge which has a radius and the insulator114 meets the electrically conductive sealing surface 112 along anadjoining edge which is generally tangential to the radius and/or meetsalong the radius. Preferably, at the interface, the electricallyconductive surface 112 is raised relative to the insulator 114. Theseand other envisioned embodiments are discussed in concurrently-filed,co-pending, commonly assigned Application Serial No. PCT/US01/11412entitled “ELECTROSURGICAL INSTRUMENT WHICH REDUCES COLLATERAL DAMAGE TOADJACENT TISSUE” by Johnson et al. and concurrently-filed, co-pending,commonly assigned Application Serial No. PCT/US01/11411 entitled“ELECTROSURGICAL INSTRUMENT WHICH IS DESIGNED TO REDUCE THE INCIDENCE OFFLASHOVER” by Johnson et al.

Insulator 114 also includes an inwardly facing finger 162 which abutspivot flange 166 and is designed to restrict/reduce proximal tissuespread and/or isolate the electrically conductive sealing surface 112from the remaining end effector assembly 100 during activation.Preferably, the electrically conductive surface 112 and the insulator114, when assembled, form a longitudinally-oriented channel 168 a, 168 bdefined therethrough for reciprocation of the knife blade 205. Moreparticularly, and as best illustrated in FIG. 14, insulator 114 includesa first channel 168 b which aligns with a second channel 168 a onelectrically conductive sealing surface 112 to form the complete knifechannel. It is envisioned that the knife channel 168 a, 168 bfacilitates longitudinal reciprocation of the knife blade 205 along apreferred cutting plane “B-B” to effectively and accurately separate thetissue 420 along the formed tissue seal 425 (See FIGS. 27, 28 and 31.

As mentioned above, jaw member 120 include similar elements whichinclude: a pivot flange 176 which has an arcuately-shaped inner surface177, a cam slot 174, and a recess 175; a jaw housing 126 which includesa groove 179 which is dimensioned to engage a ridge-like interface 171disposed along the outer periphery of an insulator 124; the insulator124 which includes an inwardly facing finger 172 which abuts pivotflange 176; and an electrically conducive sealing surface 122 which isdimensioned to securely engage the insulator 124. Likewise, theelectrically conductive surface 122 and the insulator 124, whenassembled, form a longitudinally-oriented channel 178 a, 178 b definedtherethrough for reciprocation of the knife blade 205.

Preferably, the jaw members 110 and 120 are electrically isolated fromone another such that electrosurgical energy can be effectivelytransferred through the tissue 420 to form seal 425. For example and asbest illustrated in FIGS. 14 and 15, each jaw member, e.g., 110,includes a uniquely-designed electrosurgical cable path disposedtherethrough which transmits electrosurgical energy to the electricallyconductive sealing surfaces 112, 122. More particularly, jaw member 110includes a cable guide 181 a disposed atop pivot flange 166 whichdirects cable lead 310 a towards an aperture 188 disposed through jawhousing 116. Aperture 188, in turn, directs cable lead 310 a towardselectrically conductive sealing surface 112 through a window 182disposed within insulator 114. A second cable guide 181 b secures cablelead 310 a along the predefined cable path through window 182 anddirects a terminal end 310 a′ of the cable lead 310 a into crimp-likeelectrical connector 183 disposed on an opposite side of theelectrically conductive sealing surface 112. Preferably, cable lead 310a is held loosely but securely along the cable path to permit rotationof the jaw member 110 about pivot 169.

As can be appreciated, this isolates electrically conductive sealingsurface 112 from the remaining operative components of the end effectorassembly 100 and shaft 12. Jaw member 120 includes a similar cable pathdisposed therein and therethrough which includes similarly dimensionedcable guides, apertures and electrical connectors which are not shown inthe accompanying illustrations.

FIGS. 15-17 also show the presently disclosed feed path for bothelectrosurgical cable leads 310 a and 310 b along the outer periphery ofthe shaft 12 and through each jaw member 110 and 120. More particularly,FIG. 15 shows a cross section of the electrosurgical cable leads 310 aand 310 b disposed within channels 19 a and 19 b, respectively, alongshaft 12. FIGS. 16 and 17 show the feed path of the cable leads 310 aand 310 b from the opposite channels 19 a and 19 b of the shaft 12through the pivot flanges 166 and 176 of the jaw members 110 and 120,respectively. It is contemplated that this unique cable feed path forcable leads 310 a and 310 b from the shaft 12 to the jaw members 110 and120 not only electrically isolates each jaw member 100 and 120 but alsoallows the jaw members 110 and 120 to pivot about pivot pin 160 withoutunduly straining or possibly tangling the cable leads 310 a and 310 b.Moreover, it is envisioned that the crimp-like electrical connector 183(and the corresponding connector in jaw member 120) greatly facilitatesthe manufacturing and assembly process and assures a consistent andtight electrical connection for the transfer of energy through thetissue 420. As best shown in FIG. 17, the outer surface of shaft 12 maybe covered by heat shrink tubing 500 or the like which protects thecable leads 310 a and 310 b from undue wear and tear and secures cableleads 310 a and 310 b within their respective channels 19 a and 19 b.

FIGS. 18A and 18B show the feed path of the cable leads 310 a and 310 bthrough the rotating assembly 80 which, again, allows the user addedflexibility during the use of the forceps 10 due to the uniqueness ofthe feed path. More particularly, FIG. 18A shows the feed path of cablelead 310 a through half 80 a of the rotating assembly 80 and FIG. 18Bshows the path of cable leads 310 a and 310 b as the cable leads 310 aand 310 b feed through the instrument housing 20 a, through half 80 a ofthe rotating assembly 80 and to the channels 19 a and 19 b of the shaft12. FIG. 18A only shows the feed path of cable lead 310 a through half80 a of the rotating assembly 80, however, as can be appreciated, cablelead 310 b (shown broken in FIG. 19) is positioned in a similar fashionwithin half 80 b of rotating assembly 80.

As best illustrated in FIG. 18A, it is envisioned that cable leads 310 aand 310 b are fed through respective halves 80 a and 80 b of therotating assembly 80 in such a manner to allow rotation of the shaft 12(via rotation of the rotating assembly 80) in the clockwise orcounter-clockwise direction without unduly tangling or twisting thecable leads 310 a and 310 b. More particularly, each cable lead, e.g.,310 a, is looped through each half 80 a of the rotating assembly 80 toform slack-loops 321 a and 321 b which traverse either side oflongitudinal axis “A”. Slack-loop 321 a redirects cable lead 310 aacross one side of axis “A” and slack-loop 321 b returns cable lead 310a across axis “A”. It is envisioned that feeding the cable leads 310 aand 310 b through the rotating assembly 80 in this fashion allows theuser to rotate the shaft 12 and the end effector assembly 100 withoutunduly straining or tangling the cable leads 310 a and 310 b which mayprove detrimental to effective sealing. Preferably, this loop-like cablefeed path allows the user to rotate the end effector assembly 100 about180 degrees in either direction without straining the cable leads 310 aand 310 b. The presently disclosed cable lead feed path is envisioned torotate the cable leads 310 a and 310 b approximately 178 degrees ineither direction.

FIG. 19 shows an internal view of half 80 a of the rotating assembly 80as viewed along axis “A” to highlight the internal features thereof.More particularly, at least one stop 88 is preferably positioned withineach rotating half 80 a and 80 b which operates to control the overallrotational movement of the rotating assembly 80 to about 180 degree ineither direction. The stop member 88 is dimensioned to interface with acorresponding notch 309 c disposed along the periphery of outer flange309 to prevent unintended over-rotation of the rotating assembly 80which may unduly strain one or both of the cable leads 310 a and 310 b.

FIG. 18B shows the feed path of the electrical cable leads 310 a and 310b from the housing 20 a, through the rotating assembly 80 and to theshaft 12. It is envisioned that the cable leads 310 a and 310 b aredirected through each part of the forceps 10 via a series of cable guidemembers 311 a-311 g disposed at various positions through the housing 20and rotating assembly 80. As explained below, a series of mechanicalinterfaces, e.g., 309 a, 309 b (FIG. 13) and 323 a, 323 b (FIG. 13) mayalso be dimensioned to contribute in guiding cables 310 a and 310 bthrough the housing 20 and rotating assembly 80.

Turning back to FIG. 13 which shows the exploded view of the housing 20,rotating assembly 80, trigger assembly 70 and handle assembly 30, it isenvisioned that all of these various component parts along with theshaft 12 and the end effector assembly 100 are assembled during themanufacturing process to form a partially and/or fully disposableforceps 10. For example and as mentioned above, the shaft 12 and/or endeffector assembly 100 may be disposable and, therefore,selectively/releasably engagable with the housing 20 and rotatingassembly 80 to form a partially disposable forceps 10 and/or the entireforceps 10 may be disposable after use.

Housing 20 is preferably formed from two housing halves 20 a and 20 bwhich engage one another via a series of mechanical interfaces 307 a,307 b, 307 c and 308 a, 308 b, 308 c respectively, to form an internalcavity 300 for housing the hereindescribed internal working componentsof the forceps 10. For the purposes herein, housing halves 20 a and 20are generally symmetrical and, unless otherwise noted, a componentdescribed with respect to housing half 20 a will have a similarcomponent which forms a part of housing half 20 b.

Housing half 20 a includes proximal and distal ends 301 a and 303 a,respectively. Proximal end 301 a is preferably dimensioned to receive anelectrical sleeve 99 which secures the electrosurgical cable 310(FIG. 1) within the housing 20. As best shown in FIGS. 9 and 21, pairedcable 310 splits into two electrosurgical cable leads 310 a and 310 bwhich are subsequently fed through the housing 20 to ultimately transmitdifferent electrical potentials to the opposing jaw members 110 and 120.As mentioned above, various cable guides 311 a-311 g are positionedthroughout the housing 20 and the rotating assembly 80 to direct thecable leads 310 a and 310 b to the channels 19 a and 19 b disposed alongthe outer periphery of the shaft 12.

The distal end 303 a is generally arcuate in shape such that, whenassembled, distal ends 303 a and 303 b form a collar 303 (FIG. 13) whichextends distally from the housing 20. Each distal end 303 a, 303 b ofthe collar 303 includes an outer flange 309 a, 309 b and a recess 323 a,323 b which cooperate to engage corresponding mechanical shoulders 84 a,84 b (FIG. 29) and flanges 87 a, 87 b, respectively, disposed within therotating assembly 80. As can be appreciated, the interlocking engagementof the flanges 309 a, 309 b with the shoulders 84 a, 84 b and therecesses 323 a, 323 b with the flanges 87 a, 87 b are dimensioned toallow free rotation about of the rotating assembly 80 about collar 303when assembled. As mentioned above, the stop member(s) 88 and thenotch(es) mechanically cooperate to limit rotational movement of therotating assembly 80 to avoid straining cable leads 310 a and 310 b.

Each distal end 303 a, 303 b of collar 303 also includes an inner cavity317 a and 317 b (FIGS. 9 and 21), respectively, defined therein which isdimensioned to permit free rotation of the shaft 12, knife tube 34 andcable leads 310 a and 310 b housed therein. A plurality of detents 89 alocated within rotating assembly 80 engage a corresponding plurality ofsockets 89 b (FIG. 13) disposed within rotating half 80 b to poise therotating assembly 80 in rotational relationship atop collar 303.

Housing half 20 a also includes a plurality of hub-like pivot mounts 329a, 331 a and 333 a which as explained in more detail below with respectto the operation of the instrument, cooperate with opposite hub-likepivot mounts (shown in phantom in FIG. 13) disposed on housing half 20 bto engage the free ends of pivot pins 37, 67 b and 77, respectively,which are associated with the different operating components describedbelow. Preferably, each of these mounts 329 a, 331 a and 333 a provide afixed point of rotation for each pivoting element, namely, cam link 36,handle link 65 and trigger assembly 70, respectively.

As best seen in FIGS. 11 and 13, fixed handle 50 which takes shape uponthe assembly of housing 20 includes a scallop-like outer surface 51 andan internal cavity 52 defined therein. As mentioned above with respectto the discussion of FIG. 11, these elements and the other internalelements of the fixed handle 50 cooperate with movable handle 40 toactivates the four-bar mechanical linkage which, in turn, actuates thedrive assembly 21 for imparting movement of the opposing jaw members 110and 120 relative to one another to grasp tissue 420 therebetween.

The handle assembly 30 which includes the above-mentioned fixed handle50 and movable handle 40 also includes the cam link 36 which isgenerally triangular in shape. The cam link includes an upper piston 38,a fixed pivot 37 and a handle pivot 69. Cam link is assembled within theinternal cavity 300 of housing 20 between housing halves 20 a and 20 b.More particularly, fixed pivot 37 is rotatingly mounted within fixedmounts 329 a and 329 b between opposing housing halves 20 a and 20 b andthe handle pivot 69 is rotatingly mounted within the bifurcated end ofhandle 40 through apertures 68 a and 68 b. Cam piston 38 is poisedwithin a longitudinal channel 25 c defined through the drive assembly 70(explained in further detail below with respect to the discussion of thedrive assembly 70) in abutting relationship with a compression tab 25such that movement of the handle 40 rotates piston 38 proximally againstcoil spring 22. These and the other details relating to the operationalfeatures are discussed below with reference to FIGS. 21-29.

Link 65 is also associated with the handle assembly 30 and forms anintegral part of the four-bar mechanical linkage. Link 65 includes adistal end 63 and two pivot pins 67 a and 67 b. Pivot pin 67 a engagesapertures 68 a and 68 b disposed within the movable handle 40 and pivot67 b engages fixed mounts 331 a and 331 b between housing halves 20 aand 20 b such that movement of the handle 40 towards fixed handle 50pivots link 65 about pivots 67 a and 67 b. As explained in more detailbelow, distal end 63 acts as a lockout for the trigger assembly 70.

Movable handle 40 includes a flange 92 which is preferably mounted tothe movable handle 40 by pins 46 a and 46 b which engage apertures 41 aand 41 b disposed within handle 40 and apertures 91 a and 91 b disposedwithin flange 92, respectively. Other methods of engagement are alsocontemplated, snap-lock, spring tab, etc. Flange 92 also includes at-shaped distal end 93 which, as mentioned above with respect to FIG.11, rides within a predefined channel 54 disposed within fixed handle50. Additional features with respect to the t-shaped end 93 areexplained below in the detailed discussion of the operational featuresof the forceps 10.

A drive assembly 21 is preferably positioned within the housing 20between housing halves 20 a and 20 b. As discussed above, the driveassembly 21 includes the previously described drive rod 32 and thecompression mechanism 24. Compression mechanism 24 includes acompression sleeve 27 which is telescopically and/or slidingly disposedwithin a spring mount 26. The distal end 28 of the compression sleeve 27is preferably C-shaped and dimensioned to engage the tab 33 disposed atthe proximal end of drive rod 32 such that longitudinal movement of thecompression sleeve 27 actuates the drive rod 32. The proximal end of thecompression sleeve 27 is dimensioned to engage a barbell-shapedcompression tab 25 which is disposed within a longitudinal slot 25 s ofthe spring mount 26. The compression sleeve 27 also includes alongitudinal slot or channel 25 c which is longitudinally aligned withslot 25 s and is dimensioned to receive the cam piston 38 of the camlink 36 described above.

The proximal end of spring mount 26 includes a circular flange 23 whichis dimensioned to bias the compression spring 22 once the compressionmechanism 24 is assembled and seated within housing 20 (FIG. 11). Thedistal end of spring mount 26 includes a flange 25 f which restrictsdistal movement of the tab 25 to within the slot 25 s of the springmount 26 and biases the opposite end the spring 22.

As best seen in FIG. 11, once assembled, spring 22 is poised forcompression atop spring mount 26 upon actuation of the handle assembly30. More particularly, movement of the cam piston 38 within slot 25 c(via movement of handle assembly 30) moves the tab 25 atop slot 25 s andreciprocates the compression sleeve 27 within the spring mount 26 tocompress the spring 22. Proximal movement of the compression sleeve 27imparts proximal movement to the drive rod 32 which closes jaw members110 and 120 about tissue 420 (FIG. 26). Compression of the spring 22 maybe viewed through one or more windows 340 disposed within the housinghalves, e.g., 20 b.

FIG. 13 also shows the trigger assembly 70 which activates the knifeassembly 200 as described above with respect to FIG. 12. Moreparticularly, trigger assembly 70 includes an actuator 73 having acuff-like distal end 78 which is dimensioned to receive the proximal rim35 of the knife tube 34. A drive pin 74 extends laterally from theproximal end of actuator 73. Trigger assembly 70 also includes anergonomically enhanced finger tab 72 having opposing wing-like flanges72 a and 72 b which are envisioned to facilitate gripping and firing ofthe trigger assembly during surgery.

As best shown in FIG. 11, the compression sleeve 27 is dimensioned toslide internally within actuator 73 when the forceps 10 is assembled.Likewise, the actuator 73, when activated, can slide distally along theouter periphery of compression sleeve 27 to actuate the knife assembly200 as described above with respect to FIG. 12. The drive pin 74 isdimensioned to ride along a pair of guide rails 71 a and 71 b disposedwithin a bifurcated tail portion of finger tab 72 which includes ends 76a and 76 b, respectively.

A hinge or pivot pin 77 mounts the finger tab 72 between housing halves20 a and 20 within mounts 333 a and 333 b. A torsion spring 75 may alsobe incorporated within the trigger assembly 70 to facilitate progressiveand consistent longitudinal reciprocation of the actuator 73 and knifetube 34 to assure reliable separation along the tissue seal 425 (FIGS.27 and 28). In other words, the trigger assembly 70 is configured in aproximal, “pre-loaded” configuration prior to activation. This assuresaccurate and intentional reciprocation of the knife assembly 200.Moreover, it is envisioned that the “pre-load” configuration of thetorsion spring 75 acts as an automatic recoil of the knife assembly 200to permit repeated reciprocation through the tissue as needed. Asmentioned above, a plurality of gripping elements 71 is preferablyincorporated atop the finger tab 72 and wing flanges 72 a and 72 b toenhance gripping of the finger tab 72.

Preferably, the trigger assembly 70 is initially prevented from firingdue to the unique configuration of the distal end 63 of the link 65which abuts against the finger tab 72 and “locks” the trigger assembly70 prior to actuation of the handle assembly 30. Moreover, it isenvisioned that the opposing jaw members 110 and 120 may be rotated andpartially opened and closed without unlocking the trigger assembly 70which, as can be appreciated, allows the user to grip and manipulate thetissue 420 without premature activation of the knife assembly 200. Asmentioned below, only when the t-shaped end 93 of flange 92 iscompletely reciprocated within channel 54 and seated within apre-defined catch basin 62 (explained below) will the distal end 63 oflink 65 move into a position which will allow activation of the triggerassembly 70.

The operating features and relative movements of the internal workingcomponents of the forceps 10 are shown by phantom representation anddirectional arrows and are best illustrated in FIGS. 21-29. As mentionedabove, when the forceps 10 is assembled a predefined channel 54 isformed within the cavity 52 of fixed handle 50. The channel 54 includesentrance pathway 53 and an exit pathway 58 for reciprocation of theflange 92 and the t-shaped end 93 therein. Once assembled, the twogenerally triangular-shaped members 57 a and 57 b are positioned inclose abutment relative to one another and define track 59 disposedtherebetween.

More particularly, FIGS. 21 and 22 show the initial actuation of handle40 towards fixed handle 50 which causes the free end 93 of flange 92 tomove generally proximally and upwardly along entrance pathway 53. Duringmovement of the flange 92 along the entrance and exit pathways 53 and58, respectively, the t-shaped end 93 rides along track 59 between thetwo triangular members 57 a and 57 b.

As the handle 40 is squeezed and flange 92 is incorporated into channel54 of fixed handle 50, the cam link 36, through the mechanical advantageof the four-bar mechanical linkage, is rotated generally proximallyabout pivots 37 and 69 such that the cam piston 38 biases tab 25 whichcompresses spring 22 against flange 23 of the spring mount (FIG. 23).Simultaneously, the drive rod 32 is pulled proximally by the compressionsleeve 27 which, in turn, causes cam pin 170 to move proximally withincam slots 172 and 174 and close the jaw members 110 and 120 relative toone another (FIG. 24). It is envisioned that channel 197 may bedimensioned slightly larger than needed to take into account anydimensional inconsistencies with respect to manufacturing tolerances ofthe various operating components of the end effector assembly 100 (FIG.24)

It is envisioned that the utilization of a four-bar linkage will enablethe user to selectively compress the coil spring 22 a specific distancewhich, in turn, imparts a specific load on the drive rod 32. The driverod 32 load is converted to a torque about the jaw pivot 160 by way ofcam pin 170. As a result, a specific closure force can be transmitted tothe opposing jaw members 110 and 120. It is also contemplated, thatwindow 340 disposed in the housing 20 may include graduations, visualmarkings or other indicia which provide feedback to the user duringcompression of the handle assembly 30. As can be appreciated, the usercan thus selectively regulate the progressive closure forces applied tothe tissue 420 to accomplish a particular purpose or achieve aparticular result. For example, it is envisioned that the user mayprogressively open and close the jaw members 110 and 120 about thetissue without locking the flange 93 in the catch basin 62. The window340 may include a specific visual indicator which relates to theproximal-most position of flange 93 prior to engagement within the catchbasin 62.

As mentioned above, the jaw members 110 and 120 may be opened, closedand rotated to manipulate tissue 420 until sealing is desired withoutunlocking the trigger assembly 70. This enables the user to position andre-position the forceps 10 prior to activation and sealing. Moreparticularly, as illustrated in FIG. 4, the end effector assembly 100 isrotatable about longitudinal axis “A” through rotation of the rotatingassembly 80. As mentioned above, it is envisioned that the unique feedpath of the cable leads 310 a and 310 b through the rotating assembly80, along shaft 12 and, ultimately, through the jaw members 110 and 120enable the user to rotate the end effector assembly 100 about 180degrees in both the clockwise and counterclockwise direction withouttangling or causing undue strain on the cable leads 310 a and 310 b. Ascan be appreciated, this facilitates the grasping and manipulation oftissue 420.

A series of stop members 150 a-150 f are preferably employed on theinner facing surfaces of the electrically conductive sealing surfaces112 and 122 to facilitate gripping and manipulation of tissue and todefine a gap “G” (FIG. 24) between opposing jaw members 110 and 120during sealing and cutting of tissue. A detailed discussion of these andother envisioned stop members 150 a-150 f as well as variousmanufacturing and assembling processes for attaching and/or affixing thestop members 150 a-150 f to the electrically conductive sealing surfaces112, 122 are described in commonly-assigned, co-pending U.S. ApplicationSerial No. PCT/US01/11413 entitled “VESSEL SEALER AND DIVIDER WITHNON-CONDUCTIVE STOP MEMBERS” by Dycus et al. which is herebyincorporated by reference in its entirety herein.

Once the desired position for the sealing site 425 is determined and thejaw members 110 and 120 are properly positioned, handle 40 may becompressed fully such that the t-shaped end 93 of flange 92 clears apredefined rail edge 61 located atop the triangular-shaped members 57 aand 57 b. Once end 93 clears edge 61, distal movement of the handle 40and flange 92, i.e., release, is redirected by edge 61 into a catchbasin 62 located within the exit pathway 58. More particularly, upon aslight reduction in the closing pressure of handle 40 against handle 50,the handle 40 returns slightly distally towards entrance pathway 53 butis re-directed towards exit pathway 58. At this point, the release orreturn pressure between the handles 40 and 50 which is attributable anddirectly proportional to the release pressure associated with thecompression of the drive assembly 70 causes the end 93 of flange 92 tosettle or lock within catch basin 62. Handle 40 is now secured inposition within fixed handle 50 which, in turn, locks the jaw members110 and 120 in a closed position against the tissue 420.

At this point the jaws members 100 and 120 are fully compressed aboutthe tissue 420 (FIG. 26). Moreover, the forceps 10 is now ready forselective application of electrosurgical energy and subsequentseparation of the tissue 420, i.e., as t-shaped end 93 seats withincatch basin 62, link 65 moves into a position to permit activation ofthe trigger assembly 70 (FIGS. 21 and 29).

As the t-shaped end 93 of flange 92 becomes seated within catch basin62, a proportional axial force on the drive rod 32 is maintained which,in turn, maintains a compressive force between opposing jaw members 110and 120 against the tissue 420. It is envisioned that the end effectorassembly 100 and/or the jaw members 110 and 120 may be dimensioned tooff-load some of the excessive clamping forces to prevent mechanicalfailure of certain internal operating elements of the end effector 100.

As can be appreciated, the combination of the four-bar mechanicaladvantage along with the compressive force associated with thecompression spring 22 facilitate and assure consistent, uniform andaccurate closure pressure about the tissue 420.

By controlling the intensity, frequency and duration of theelectrosurgical energy applied to the tissue 420, the user can eithercauterize, coagulate/desiccate, seal and/or simply reduce or slowbleeding. As mentioned above, two mechanical factors play an importantrole in determining the resulting thickness of the sealed tissue andeffectiveness of the seal 425, i.e., the pressure applied betweenopposing jaw members 110 and 120 and the gap distance “G” between theopposing sealing surfaces 112, 122 of the jaw members 110 and 120 duringthe sealing process. However, thickness of the resulting tissue seal 425cannot be adequately controlled by force alone. In other words, too muchforce and the two jaw members 110 and 120 would touch and possibly shortresulting in little energy traveling through the tissue 420 thusresulting in a bad tissue seal 425. Too little force and the seal 425would be too thick.

Applying the correct force is also important for other reasons: tooppose the walls of the vessel; to reduce the tissue impedance to a lowenough value that allows enough current through the tissue 420; and toovercome the forces of expansion during tissue heating in addition tocontributing towards creating the required end tissue thickness which isan indication of a good seal 425.

Preferably, the electrically conductive sealing surfaces 112, 122 of thejaw members 110, 120, respectively, are relatively flat to avoid currentconcentrations at sharp edges and to avoid arcing between high points.In addition and due to the reaction force of the tissue 420 whenengaged, jaw members 110 and 120 are preferably manufactured to resistbending. For example, the jaw members 110 and 120 may be tapered alongthe width thereof which is advantageous for two reasons: 1) the taperwill apply constant pressure for a constant tissue thickness atparallel; 2) the thicker proximal portion of the jaw members 110 and 120will resist bending due to the reaction force of the tissue 420.

It is also envisioned that the jaw members 110 and 120 may be curved inorder to reach specific anatomical structures. For example, it iscontemplated that dimensioning the jaw members 110 and 120 at an angleof about 50 degrees to about 70 degrees is preferred for accessing andsealing specific anatomical structures relevant to prostatectomies andcystectomies, e.g., the dorsal vein complex and the lateral pedicles. Itis also envisioned that the knife assembly 200 (or one or more of thecomponents thereof) may be made from a semi-compliant material or may bemulti-segmented to assure consistent, facile and accurate cuttingthrough the above envisioned curved jaw member 110 and 120.

As mentioned above, at least one jaw member, e.g., 110 may include astop member, e.g., 150 a, which limits the movement of the two opposingjaw members 110 and 120 relative to one another (FIGS. 6 and 7).Preferably, the stop member, e.g., 150 a, extends from the sealingsurface 112, 122 a predetermined distance according to the specificmaterial properties (e.g., compressive strength, thermal expansion,etc.) to yield a consistent and accurate gap distance “G” during sealing(FIG. 24). Preferably, the gap distance between opposing sealingsurfaces 112 and 122 during sealing ranges from about 0.001 inches toabout 0.005 inches and, more preferably, between about 0.002 and about0.003 inches.

Preferably, stop members 150 a-150 f are made from an insulativematerial, e.g., parylene, nylon and/or ceramic and are dimensioned tolimit opposing movement of the jaw members 110 and 120 to within theabove mentioned gap range. It is envisioned that the stop members 150a-150 f may be disposed one or both of the jaw members 110 and 120depending upon a particular purpose or to achieve a particular result.Many different configurations for the stop members 150 a-150 f arediscussed in detail in commonly-assigned, co-pending U.S. ApplicationSerial No. PCT/US01/11413 entitled “VESSEL SEALER AND DIVIDER WITHNON-CONDUCTIVE STOP MEMBERS” by Dycus et al. which is herebyincorporated by reference in its entirety herein.

One particular stop member configuration is shown in FIG. 33 which showsa single, circular stop member 150 d disposed on either side of theknife channel 178 a near the proximal-most portion of one of the sealingsurfaces, e.g., 112. Two sets of circular stop member pairs 150 e aredisposed in the middle portion of sealing surface 112 on either side ofthe knife channel 178 a and a single, circular stop member 150 f isdisposed at the distal-most portion of sealing surface 112 on eitherside of the knife channel 178 a. It is envisioned any of the variousstop member configurations contemplated herein may be disposed on one orboth sealing surfaces 112, 122 depending upon a particular purpose or toachieve a particular result. Moreover, it is envisioned that the stopmembers 150 a-150 f may be disposed on one side of the knife channel 178a according to a specific purpose.

Preferably, the non-conductive stop members 150 a-150 f are molded ontothe jaw members 110 and 120 (e.g., overmolding, injection molding,etc.), stamped onto the jaw members 110 and 120 or deposited (e.g.,deposition) onto the jaw members 110 and 120. For example, one techniqueinvolves thermally spraying a ceramic material onto the surface of thejaw member 110 and 120 to form the stop members 150 a-150 f. Severalthermal spraying techniques are contemplated which involve depositing abroad range of heat resistant and insulative materials on varioussurfaces to create stop members for controlling the gap distance betweenelectrically conductive surfaces 112, 122. Other techniques fordisposing the stop members 150 a-150 f on the electrically conductivesurfaces 112 and 122 are also contemplated, e.g., slide-on, snap-on,adhesives, molds, etc.

Further, although it is preferable that the stop members 150 a-150 fprotrude about 0.001 inches to about 0.005 inches and preferably about0.002 inches to about 0.003 inches from the inner-facing surfaces 112,122 of the jaw member 110 and 120, in some cases it may be preferable tohave the stop members 150 a-150 f protrude more or less depending upon aparticular purpose. For example, it is contemplated that the type ofmaterial used for the stop members 150 a-150 f and that material'sability to absorb the large compressive closure forces between jawmembers 110 and 120 will vary and, therefore, the overall dimensions ofthe stop members 150 a-150 f may vary as well to produce the desired gapdistance “G”.

In other words, the compressive strength of the material along with thedesired or ultimate gap distance “G” required (desirable) for effectivesealing are parameters which are carefully considered when forming thestop members 150 a-150 f and one material may have to be dimensioneddifferently from another material to achieve the same gap distance ordesired result. For example, the compressive strength of nylon isdifferent from ceramic and, therefore, the nylon material may have to bedimensioned differently, e.g., thicker, to counteract the closing forceof the opposing jaw members 110 and 120 and to achieve the same desiredgap distance “G′” when utilizing a ceramic stop member.

As best shown in FIGS. 27 and 28, as energy is being selectivelytransferred to the end effector assembly 100, across the jaw members 110and 120 and through the tissue 420, a tissue seal 425 forms isolatingtwo tissue halves 420 a and 420 b. At this point and with other knownvessel sealing instruments, the user must remove and replace the forceps10 with a cutting instrument (not shown) to divide the tissue halves 420a and 420 b along the tissue seal 425. As can be appreciated, this isboth time consuming and tedious and may result in inaccurate tissuedivision across the tissue seal 425 due to misalignment or misplacementof the cutting instrument along the ideal tissue cutting plane “B-B”.

As explained in detail above, the present disclosure incorporates aknife assembly 200 which, when activated via the trigger assembly 70,progressively and selectively divides the tissue 420 along the idealtissue plane “B-B” in an accurate and precise manner to effectively andreliably divide the tissue 420 into two sealed halves 420 a and 420 b(FIG. 31) with a tissue gap 430 therebetween. The reciprocating knifeassembly 200 allows the user to quickly separate the tissue 420immediately after sealing without substituting a cutting instrumentthrough a cannula or trocar port 410. As can be appreciated, accuratesealing and dividing of tissue 420 is accomplished with the sameforceps. It is envisioned that knife blade 205 may also be coupled tothe same or an alternative electrosurgical energy source to facilitateseparation of the tissue 420 along the tissue seal 425 (Not shown).

Moreover, it is envisioned that the angle of the blade tip 207 of theknife blade 205 may be dimensioned to provide more or less aggressivecutting angles depending upon a particular purpose. For example, theblade tip 207 may be positioned at an angle which reduces “tissue wisps”associated with cutting. More over, the blade tip 207 may be designedhaving different blade geometries such as serrated, notched, perforated,hollow, concave, convex etc. depending upon a particular purpose or toachieve a particular result.

Although it is envisioned that the blade tip 207 have a relatively sharpleading edge, it is also envisioned that the blade tip 207 may besubstantially blunt or dull. More particularly, it is contemplated thatthe combination of the closure force between the jaw members 110 and 120together with the uniquely designed stop members 150 a-150 f grip andhold the tissue firmly between the jaw members 110 and 120 to permitcutting of the tissue by blade tip 207 even if tip 207 is substantiallyblunt. As can be appreciated, designing the blade tip 207 blunteliminates concerns relating to utilizing sharp objects with thesurgical field.

Once the tissue 420 is divided into tissue halves 420 a and 420 b, thejaw members 110 and 120 may be opened by re-grasping the handle 40 asexplained below. It is envisioned that the knife assembly 200 generallycuts in a progressive, uni-directional fashion (i.e., distally),however, it is contemplated that the knife blade may dimensioned to cutbi-directionally as well depending upon a particular purpose. Forexample, the force associated with the recoil of the trigger spring 75may be utilized to with a second blade (not shown) which is designed tocut stray tissue wisps or dangling tissue upon recoil of the knifeassembly.

As best shown in FIG. 32, re-initiation or re-grasping of the handle 40again moves t-shaped end 93 of flange 92 generally proximally along exitpathway 58 until end 93 clears a lip 61 disposed atop triangular-shapedmembers 57 a, 57 b along exit pathway 58. Once lip 61 is sufficientlycleared, handle 40 and flange 92 are fully and freely releasable fromhandle 50 along exit pathway 58 upon the reduction of grasping/grippingpressure which, in turn, returns the jaw members 110 and 120 to theopen, pre-activated position.

From the foregoing and with reference to the various figure drawings,those skilled in the art will appreciate that certain modifications canalso be made to the present disclosure without departing from the scopeof the present disclosure. For example, it may be preferable to addother features to the forceps 10, e.g., an articulating assembly toaxially displace the end effector assembly 100 relative to the elongatedshaft 12.

It is also contemplated that the forceps 10 (and/or the electrosurgicalgenerator used in connection with the forceps 10) may include a sensoror feedback mechanism (not shown) which automatically selects theappropriate amount of electrosurgical energy to effectively seal theparticularly-sized tissue grasped between the jaw members 110 and 120.The sensor or feedback mechanism may also measure the impedance acrossthe tissue during sealing and provide an indicator (visual and/oraudible) that an effective seal has been created between the jaw members110 and 120.

Moreover, it is contemplated that the trigger assembly 70 may includeother types of recoil mechanism which are designed to accomplish thesame purpose, e.g., gas-actuated recoil, electrically-actuated recoil(i.e., solenoid), etc. It is also envisioned that the forceps 10 may beused to dive/cut tissue without sealing. Alternatively, the knifeassembly may be coupled to the same or alternate electrosurgical energysource to facilitate cutting of the tissue.

Although the figures depict the forceps 10 manipulating an isolatedvessel 420, it is contemplated that the forceps 10 may be used withnon-isolated vessels as well. Other cutting mechanisms are alsocontemplated to cut tissue 420 along the ideal tissue plane “B-B”. Forexample, it is contemplated that one of the jaw members may include acam-actuated blade member which is seated within one of the jaw memberswhich, upon reciprocation of a cam member, is biased to cut tissue alonga plane substantially perpendicular to the longitudinal axis “A”.

Alternatively, a shape memory alloy (SMAs) may be employed to cut thetissue upon transformation from an austenitic state to a martenisticstate with a change in temperature or stress. More particularly, SMAsare a family of alloys having anthropomorphic qualities of memory andtrainability and are particularly well suited for use with medicalinstruments. SMAs have been applied to such items as actuators forcontrol systems, steerable catheters and clamps. One of the most commonSMAs is Nitinol which can retain shape memories for two differentphysical configurations and changes shape as a function of temperature.Recently, other SMAs have been developed based on copper, zinc andaluminum and have similar shape memory retaining features.

SMAs undergo a crystalline phase transition upon applied temperatureand/or stress variations. A particularly useful attribute of SMAs isthat after it is deformed by temperature/stress, it can completelyrecover its original shape on being returned to the originaltemperature. This transformation is referred to as a thermoelasticmartenistic transformation.

Under normal conditions, the thermoelastic martenistic transformationoccurs over a temperature range which varies with the composition of thealloy, itself, and the type of thermal-mechanical processing by which itwas manufactured. In other words, the temperature at which a shape is“memorized” by an SMA is a function of the temperature at which themartensite and austenite crystals form in that particular alloy. Forexample, Nitinol alloys can be fabricated so that the shape memoryeffect will occur over a wide range of temperatures, e.g., −2700 to+1000 Celsius.

Although the jaw members as shown and described herein depict the jawmembers movable in a pivotable manner relative to one another to grasptissue therebetween, it is envisioned that the forceps may be designedsuch that the jaw members are mounted in any manner which move one orboth jaw members from a first juxtaposed position relative to oneanother to second contact position against the tissue.

It is envisioned that the outer surface of the end effectors may includea nickel-based material, coating, stamping, metal injection moldingwhich is designed to reduce adhesion between the end effectors (orcomponents thereof) with the surrounding tissue during activation andsealing. Moreover, it is also contemplated that the tissue contactingsurfaces 112 and 122 of the end effectors may be manufactured from one(or a combination of one or more) of the following materials:nickel-chrome, chromium nitride, MedCoat 2000 manufactured by TheElectrolizing Corporation of OHIO, inconel 600 and tin-nickel. Thetissue contacting surfaces may also be coated with one or more of theabove materials to achieve the same result, i.e., a “non-stick surface”.Preferably, the non-stick materials are of a class of materials thatprovide a smooth surface to prevent mechanical tooth adhesions. As canbe appreciated, reducing the amount that the tissue “sticks” duringsealing improves the overall efficacy of the instrument.

Experimental results suggest that the magnitude of pressure exerted onthe tissue by the seal surfaces 112 and 122 is important in assuring aproper surgical outcome. Tissue pressures within a working range ofabout 3 kg/cm2 to about 16 kg/cm2 and, preferably, within a workingrange of 7 kg/cm2 to 13 kg/cm2 have been shown to be effective forsealing arteries and vascular bundles. Preferably, the four-bar handleassembly 30, spring 22 and drive assembly are manufactured anddimensioned such that the cooperation of these working elements, i.e.,the four-bar handle assembly 30 (and the internal working componentsthereof), the spring 22 and drive assembly 21, maintain tissue pressureswithin the above working ranges. Alternatively, the handle assembly 30,the spring 22 or the drive assembly 30 may be manufactured anddimensioned to produce tissue pressures within the above working rangeindependently of the dimensions and characteristic of the other of theseworking elements.

As mentioned above, it is also contemplated that the tissue sealingsurfaces 112 and 122 of the jaw members 110 and 120 can be made from orcoated with these non-stick materials. When utilized on the sealingsurfaces 112 and 122, these materials provide an optimal surface energyfor eliminating sticking due in part to surface texture andsusceptibility to surface breakdown due electrical effects and corrosionin the presence of biologic tissues. It is envisioned that thesematerials exhibit superior non-stick qualities over stainless steel andshould be utilized on the forceps 10 in areas where the exposure topressure and electrosurgical energy can create localized “hot spots”more susceptible to tissue adhesion. As can be appreciated, reducing theamount that the tissue “sticks” during sealing improves the overallefficacy of the instrument.

As mentioned above, the non-stick materials may be manufactured from one(or a combination of one or more) of the following “non-stick”materials: nickel-chrome, chromium nitride, MedCoat 2000, Inconel 600and tin-nickel. For example, high nickel chrome alloys, Ni200, Ni201(˜100% Ni) may be made into electrodes or sealing surfaces by metalinjection molding, stamping, machining or any like process. Also and asmentioned above, the tissue sealing surfaces 112 and 122 may also be“coated” with one or more of the above materials to achieve the sameresult, i.e., a “non-stick surface”. For example, Nitride coatings (orone or more of the other above-identified materials) may be deposited asa coating on another base material (metal or nonmetal) using a vapordeposition manufacturing technique.

One particular class of materials disclosed herein has demonstratedsuperior non-stick properties and, in some instances, superior sealquality. For example, nitride coatings which include, but not are notlimited to: TiN, ZrN, TiAlN, and CrN are preferred materials used fornon-stick purposes. CrN has been found to be particularly useful fornon-stick purposes due to its overall surface properties and optimalperformance. Other classes of materials have also been found to reducingoverall sticking. For example, high nickel/chrome alloys with a Ni/Crratio of approximately 5:1 have been found to significantly reducesticking in bipolar instrumentation. One particularly useful non-stickmaterial in this class is Inconel 600. Bipolar instrumentation havingsealing surfaces 112 and 122 made from or coated with Ni200, Ni201(˜100% Ni) also showed improved non-stick performance over typicalbipolar stainless steel electrodes.

By way of example, chromium nitride may be applied using a physicalvapor deposition (PVD) process that applies a thin uniform coating tothe entire electrode surface. This coating produces several effects: 1)the coating fills in the microstructures on the metal surface thatcontribute to mechanical adhesion of tissue to electrodes; 2) thecoating is very hard and is a non-reactive material which minimizesoxidation and corrosion; and 3) the coating tends to be more resistivethan the base material causing electrode surface heating which furtherenhances desiccation and seal quality.

The Inconel 600 coating is a so-called “super alloy” which ismanufactured by Special Metals, Inc. located in Conroe Tex. The alloy isprimarily used in environments which require resistance to corrosion andheat. The high Nickel content of Inconel makes the material especiallyresistant to organic corrosion. As can be appreciated, these propertiesare desirable for bipolar electrosurgical instruments which arenaturally exposed to high temperatures, high RF energy and organicmatter. Moreover, the resistivity of Inconel is typically higher thanthe base electrode material which further enhances desiccation and sealquality.

As disclosed herein the present invention relates to the transfer ofelectrosurgical energy though opposing electrically conductive sealingsurfaces having different electrical potentials to effect vesselsealing. However, it is also contemplated that the presently disclosedembodiments discussed herein may be designed to seal the tissuestructure using so-called “resistive heating” whereby the surfaces 112and 122 are not necessarily electrically conductive surfaces. Rather,each of the surfaces 112 and 122 is heated much like a conventional “hotplate” such that the surfaces 112 and 122 cooperate to seal the tissueupon contact (or upon activation of a switch (not shown) whichselectively heats each surface 112 and 122 upon activation). With thisembodiment, the resistive heating is achieved using large heating blocks1500 (See FIGS. 35A and 35B), resistive heating wire, flexible foilheaters, resistance wire flexible heaters, and/or an externally heatedelement. By controlling the temperature between a range of about 125 toabout 150 degrees Celsius, controlling the pressure between a range ofabout 100 psi to about 200 psi, and regulating the and gap distance.

It is also envisioned that the tissue may be sealed and/or fused usingradio frequency (RF) energy. With this embodiment, the electrodes whichtransmit the RF energy may be configured as a large solid blocks or amultiple smaller blocks separated by an insulator. More particularly,the surgeon can selectively regulate the transmission of RF energy to apair of thermally isolated jaw members 110 and 120 which, in turn,transmits the RF energy through the tissue which acts as a resistivemedium. By regulating the RF energy, the temperature of the tissue iseasily controlled. Moreover and as explained in the various embodimentsdescribed above, the closing pressure between the jaw members 110 and120 may be selectively regulated as well by adjusting one or more of theelements of the handle assembly 30, e.g., movable handle 40, fixedhandle 50, flange 92, track 54, etc.

Preferably, the closing pressure is in the range of about 100 to about200 psi. It has been determined that by controlling the RF energy andpressure and maintaining a gap distance “G” in the range of about 0.005millimeters to about 0.015 millimeters between the conductive surfaces112 and 122, effective and consistent tissue sealing may be achieved ina broad range of tissue types.

Alternatively, the forceps 10 may employ any combination of one or moreof the above heating technologies and a switch (not shown) which allowsthe surgeon the option of the different heating technology.

Although the presently described forceps is designed to seal and dividetissue through standard-sized cannulas, one envisioned embodiment of thepresent disclosure includes a reduced-diameter shaft 12 and end effectorassembly 100 which is specifically dimensioned to fit through a 5 mmcannula. As can be appreciated, utilizing a smaller-sized surgicalinstrument can be extremely beneficial to the patient (i.e., reducedtrauma, healing and scar tissue).

Preferably, the presently disclosed forceps is designed to electricallycouple to a foot switch (not shown) which allows the surgeon toselectively control the electrosurgical energy transferred to thetissue. FIGS. 34A and 34B show an alternate embodiment of the presentdisclosure wherein the forceps is activates via a handswitch 1200located on the trigger assembly 70. More particularly, handswitch 1200includes a pair of wafer switches 1210 which are disposed on either sideof the trigger 70. The wafer switches 1210 cooperate with an electricalconnector 1220 disposed within the housing 20. It is envisioned that thewafer switches 1210 are mounted relative to pivot pin 77 such that uponactivation of the trigger assembly 70 the wafer switches 1210 areintentionally moved out of electrical contact with connector 1220. Ascan be appreciated, this prevents accidental activation of the jawmembers 110 and 120 during cutting. Alternatively, other safety measuresmay also be employed, e.g., a cover plate which insulates the switches1210 from the connector 1220 upon actuation of the trigger assembly 70,a cut-off switch, etc.

As mentioned above, it is also envisioned that the knife blade 205 maybe energized. It is envisioned that the wafer switches could bereconfigured such that in one position, the wafer switches activate thejaw members 110 and 120 upon actuation and in another position, thewafer switches activate the knife blade 205. Alternatively, the waferswitches may be designed as mentioned upon (i.e., with a singleelectrical connector 1220) which energizes both the blade 205 and thejaw members 110 and 120 simultaneously. In this case, the blade 205 mayneed to be insulated to prevent shorting.

As can be appreciated, locating the handswitch 1200 on the forceps 10has many advantages. For example, the handswitch reduces the amount ofelectrical cable in the operating room and eliminates the possibility ofactivating the wrong instrument during a surgical procedure due to“line-of-sight” activation. Moreover, decommissioning the handswitch1200 when the trigger is actuated eliminates unintentionally activatingthe device during the cutting process.

It is also envisioned that the handswitch 1200 may be disposed onanother part of the forceps 10, e.g., the handle assembly 30, rotatingassembly, housing 20, etc. In addition, although wafer switches areshown in the drawings, other types of switches employed which allow thesurgeon to selectively control the amount of electrosurgical energy tothe jaw members or the blade 205, e.g., toggle switches, rockerswitches, flip switches, etc.

It is also contemplated that in lieu of a knife blade 205, the presentdisclosure may include a so-called “hot-wire” 305 (FIG. 40)interdisposed between the two jaw members 110 and 120 which isselectively activatable by the user to divide the tissue after sealing.More particularly, a separate wire 305 is mounted between the jawmembers, e.g., 110 and 120, and is selectively movable and energizableupon activation of the trigger assembly 70, a handswitch 1200, etc. Itis also envisioned that the “hot wire” 305 may be configured such thatthe user can move the wire 305 in an inactivated or activated statewhich as can be appreciated would allow the user to cut the tissue on areverse stroke if desired. For example, the hot wire 305 may be securedto one jaw member, e.g., 110, and held in friction fit engagementagainst the other jaw member, e.g., 120, to allow the tissue or vesselto pass between the jaw members 110, 120 when grasping and/or whenmoving the hot wire 305 in an inactivated state distally. Once sealed,the user retracts the wire 305 while energizing the hot wire 305 to cutthe tissue on the revises stroke.

It is also contemplated that the hot wire 305 may be segmented with eachend secured to a respective jaw member 110, 120 (not shown). This wouldallow the two opposing hot wires to freely pivot in one direction (i.e.,to allow through movement of the tissue between the jaw members 110, 120in one direction, e.g., upon retraction) and limit the through movementof the tissue in the opposite direction.

In another embodiment, the hot wire 305 may include a hot (i.e.,uninsulated) leading edge and an insulated trailing edge which willprevent charring on the return stroke.

It is envisioned that the presently disclosed jaw members 110 and 120can include intermittent sealing patterns 1460 a (See FIG. 35C) and 1460b (See FIG. 35D). It is contemplated that the intermittent sealingpatterns 1460 a, 1460 b promote healing by maintaining tissue viabilityand reducing collateral damage to tissue outside the tissue sealingarea. It is know that reduced tissue damage promotes healing by reducingthe chance of tissue necrosis through continued vascularization. Theintermittent sealing patterns 1460 a, 1460 b of FIGS. 35A and 35B,respectively, deliver thermal energy to controlled regions, isolated byinsulation from neighboring seal regions. The patterns are preferablydesigned to maximize seal strength yet provide a feasible path forvascularization.

FIGS. 36-38B show an alternate embodiment of the present disclosurewherein the forceps 10 includes a longitudinally reciprocating tube-likecutter 2000 disposed about the outer periphery of shaft 12. The cutter2000 is preferably designed to cut tissue 420 along the above-identifiedideal seal plane “B-B” after the tissue 420 is sealed which, as can beappreciated, typically requires the surgeon to re-grasp the tissue 420to align the tube cutter 2000 to longitudinally reciprocate along theintended cutting path of seal plane “B-B”. More particularly, the tubecutter 2000 includes an elongate tube 2012 having an interior chamber2032 which slidingly reciprocates shaft 12 and a cutting portion 2014having a generally U-shaped notched blade 2020. Preferably, the tubecutter 2000 is generally thin-walled having a thickness of approximately1.0-5.0 mm.

A recessed or offset cutting area 2018 is provided adjacent the U-shapedblade 2020 and includes a pair of adjacent cutting edges 2022 a and 2022b for cutting tissue 420 clamped by jaws members 110 and 120. As can beappreciated, the adjacent cutting edges 2022 a and 2022 b are disposedalong the inner periphery of the U-shaped blade 2020.

Preferably, the recessed cutting area 2018, i.e., the U-shaped blade2020, includes a chamfered or beveled surface 2024 which bevels inwardlyfrom the outer surface of tube 2012 to avoid incidental contact withsurrounding tissue during manipulation and handling, i.e., theinwardly-angled beveled surface 2024 avoids undesirable blade 2020 totissue contact before intentional activation by the surgeon. Further,since intended cutting area 2018 is recessed, forceps 10 can still beused for positioning vessels or tissue 420 being held between jawmembers 110 and 120 without the fear of cutting or nicking the tissue orvessels 420 during use. In one embodiment, the beveled surface 2024 isbeveled at approximately a 30-45 degree angle from the outer surface ofelongate tube 2012.

The cutting area 2014 also includes two arms 2025 a and 2025 b whichextend distally from blade 2020. Preferably, the two arms 2025 a and2025 b lie in substantially the same plane as the outer periphery of theelongated tube 2012 and are dimensioned to facilitate introduction or“feeding” of the tissue 420 into the recessed or offset cutting area2018. More particularly, each arm 2025 a and 2025 b includes a straightportion 2030 a and 2030 b, respectively, which both cooperate tointroduce tissue 420 into the cutting are 2018 upon distal movement ofthe tube cutter 2000 towards the tissue 420. A rounded distal end 2033 aand 2033 b may be included on one or both of the distal ends of thestraight portions 2030 a and 2030 b, respectively, to facilitatedelicate positioning the tissue 420 within the cutting area 2018. Forexample and as best shown in FIG. 36, the tissue 420 is initiallyintroduced into the cutting area 2018 between distal ends 2033 a and2033 b. As the cutter 2000 moves distally, i.e., upon activation asexplained in more detail below, the tissue 420 is guided by the straightportions 2030 a and 2030 b into the cutting area 2018 and into contactwith the cutting edges 2022 a and 2022 b.

Preferably, the cutter 2000 includes a mechanical actuator 2050 whichactivates the cutting 2000 once the tissue 420 is grasped and/or graspedand sealed between the jaw members 110 and 120. It is envisioned thatthe mechanical actuator 2050 can be manually (e.g., trigger) orautomatically activated depending upon a particular purpose or uponactivation of a particular event or timed sequence. The mechanicalactuator 2050 may include one or more safety features, e.g., lockouttabs, electrical circuits, sensor feedback mechanisms (not shown) toprevent accidental activation of the cutter 2000 during grasping orsealing. Simply, the cutter 2000 may be prevented from activation if thejaw members 110 and 120 are disposed in an open configuration. It isalso envisioned that the cutter 2000 may be activated prior to or aftervessel sealing depending upon a particular purpose. Moreover, and asbest illustrated by FIG. 38B, the cutter 2000 may be coupled to a sourceof electrosurgical energy, e.g., RF, ultrasonic, etc., or resistivelyheated to facilitate cutting. For example, a second electrosurgicalgenerator 2060 (or the same generator which energizes the jaw members110 and 120) may be coupled to a lead 2062 which supplieselectrosurgical energy to the cutter 2000. Alternatively, the cutter2000 may simply mechanically cut tissue 420.

As best illustrated in FIG. 38A, it is also envisioned that the cutter2000 may include serrated cutting edges 2128 a and 2128 b to enhancecutting. Alternatively, it is also contemplated that the cutting edges2028 a and 2028 b may be substantially dull and yet still cut the tissue420 one sealed. For example, the cutter 2000 may include a spring-likeactuator (not shown) which rapidly advances the cutting edges 2028 a and2028 b (or 2022 a and 2022 b) through the tissue 420 with apredetermined force which is enough to cut the tissue 420 along the sealplane “B-B” or between two seals.

As best shown in FIG. 38B, the cutter may include a coating 2222 tofacilitate cutting the tissue 420. The coating can include a resinousfluorine containing polymers or polytetrafluoroethylene commonly soldunder the trademark Teflon® (or other Teflon-like substance) tofacilitate mechanical cutting or may be an electrically conductivecoating to facilitate electrosurgical cutting. Alternatively, thecoating 2222 could also be electrically insulative in nature to reduceflashover or thermal spread during activation, or may be designed toreduce sticking. Many of these coatings are described in Applicants'co-pending earlier applications which are all incorporated by referencein their entirely herein, namely, U.S. application Ser. No. 10/116,944,PCT Application Serial No. PCT/US02/01890 and PCT Application Serial No.PCT/US01/11340.

As best illustrated in the comparison of FIGS. 37A and 37B, the tubecutter 2000 is designed to longitudinally reciprocate along longitudinalaxis “AA” to cut tissue 420 adjacent the jaw members 110 and 120 alongthe tissue seal plane “B-B”. As can be appreciated, this typicallyrequires re-grasping the tissue 420 such that the tissue sealing plane“B-B” is disposed on the cutting side of jaw members 110 and 120.Alternatively and as shown in FIG. 37B, the cutter 2000 may be designedto rotate in a cork-screw-like manner as it moves distally through thetissue 420. This may enhance the cutting process. It is also envisionedthat a cutter 2000 may be designed such that the cutter 2000 is disposedwithin a recessed portion of one of the two jaw members, e.g., 110, suchthat the cutter 2000 simply rotates through the tissue 420 or around thejaw member 110 without moving along the longitudinal axis “AA” (or onlymoving minimally along axis “AA”).

The tube cutter 2000 also includes an elongated channel 2040 disposed onthe opposite side of the u-shaped blade 2020. The channel 2040 isnecessary to facilitate unimpeded distal movement of the cutter 2000over the jaw members 110 and 120 and allow the opposite (i.e., uncut)end of the tissue 420 to move freely proximally past the jaw members 110and 120 during the cutting process. Alternatively, the cutter 2000 maybe designed such that the cutter 2000 is generally arcuate orsleeve-like and is not tubular in fashion. This design also allows freeproximal movement of the uncut tissue 420 end past the jaw members 110and 120 during cutting.

FIGS. 39A and 39B shows yet another embodiment of the forceps 3000 ofthe present disclosure wherein a unilateral jaw closure mechanism 3010is utilized to grasp tissue 420. More particularly, the forceps 3000includes a first or upper jaw member 3110 and a second or lower jawmember 3120 disposed at the distal end of an elongated shaft 3012. Theunilateral closure mechanism 3010 is designed for use with laparoscopic,bipolar or monopolar electrosurgical devices as described herein.

The unilateral closure mechanism 3010 includes one stationary jaw member3120 mounted to the shaft 3012 and pivoting jaw member 3110 mountedabout a pivot pin 3160 attached to the shaft 3012. A reciprocatingsleeve 3130 is disposed about the outer periphery of the shaft 3012 andis preferably remotely operable by a user. The pivoting jaw 3110includes a detent or protrusion 3140 which extends from jaw member 3110through an aperture 3150 disposed within the outer sleeve 3130. Thepivoting jaw 3110 is actuated by sliding the sleeve 3130 axially alongthe outside of shaft 3012 such that the aperture 3150 abuts against thedetent 3140 on the pivoting jaw 3110. Pulling the sleeve proximallycloses the jaw members 3110 and 3120 about tissue 420 graspedtherebetween and pushing the sleeve 3130 distally open the jaw members3110 and 3120 for approximation.

As best illustrated in FIGS. 39B and 39C of the present disclosure, ablade or knife channel 3170 runs through the center of the jaw members3110 and 3120 such that a blade 3190 can cut the tissue 420 graspedbetween the jaw members 3110 and 3120 only while the jaws are closed.More particularly, the blade 3190 can only be advanced through thetissue 420 when the jaw members 3110 and 3120 are closed thus preventingaccidental or premature activation of the blade 3190 through the tissue420. Put simply, the knife channel 3170 is blocked when the jaws members3110 and 3120 are opened and aligned for activation when the jaw members3110 and 3120 are closed. In addition, the unilateral closure mechanism3010 can be structured such that electrical energy can be routed throughthe sleeve 3130 at the protrusion contact 3180 point with the sleeve3130 or using a “brush” or lever (not shown) to contact the back of themoving jaw 3110 when the jaw closes. It is envisioned that the jawmember 3110 may be closed and energized simultaneously or independentlyby a separate actuator (not shown).

More particularly, when the sleeve 3130 is pushed distally, the proximalmost portion of the aperture 3150 abuts against the protrusion to pivotthe jaw member 3110 into the open configuration. Preferably, the pointof contact 3155 between the aperture and the protrusion 3140 isinsulated to prevent premature activation of the forceps 3000. When thesleeve is pulled proximally, the distal most portion of the sleeve abutsagainst the protrusion 3140 and closes the jaw member 3110. Preferably,the distal most contact 3180 and provides electrical continuity to thejaw members 3110 and 3120 through the sleeve 3130 for sealing purposes.

As can be appreciated, these designs provide at least two importantsafety features: 1) the blade 3190 cannot extend while the jaw members3110 and 3120 are opened; and 2) electrical continuity to the jawmembers 3110 and 3120 is made only when the jaws are closed.

It is envisioned that the moving jaw 3110 may also function as the blade3190 with mechanical energy, electrical energy or a combination of bothused for cutting. For example, the blade channel 3170 could include amechanical cutting mechanism or an electromechanical cutting mechanism(as described elsewhere herein) which is separately actuated once thejaw members 3110 and 3120 are closed about the tissue 420. It is alsoenvisioned that the sleeve 3130 may be biased against a spring assembly(not shown) to provide increased mechanical advantage during activation.It is contemplated that various mechanisms may be employed to provide amechanical advantage to increase the closure force between jaw members3110 and 3120, e.g., two, three and/or four-bar linkages, hydraulicmechanisms, electro-assisted actuators, cam mechanisms, gear assemblies,etc.

Another embodiment of the present disclosure includes the use of a hardanodized aluminum 3200 with or without the use of a synthetic sealedcoating 3300 (See FIGS. 39A and 39B) made from a resinous fluorinecontaining polymers or polytetrafluoroethylene commonly sold under thetrademark Teflon® on electrically non-conductive components of one orboth of the jaw members 3110 and 3120 (i.e., the areas surrounding theconductive surfaces) to control the electrical path between the two jawmembers 3110 and 3120 during electrosurgical activation and reducesticking. Other materials which tend to reduce tissue adherence include:nickel-chrome, chromium nitride, Ni200, Ni201, inconel 600, tin-nickel.It is envisioned that utilizing a hard anodized aluminum 3200 on atleast one jaw member's 3110 non-sealing surface electrically isolatesthe jaw members 3110 and 3120 from one another and confines theelectrosurgical energy between the conductive sealing surfaces. Thenon-stick coating 3300 reduces undesirable sticking of tissue 420 to jawcomponents during the sealing process.

Preferably, the hard anodized aluminum 3200 has a high dielectricstrength and good wear properties and has a thickness of about 0.001 toabout 0.003 inches. It has been found that electrically insulating thealuminum jaws 3110 and 3120 from other surrounding components confinesthe electrical path to between the jaw members 3110 and 3120 andeliminates alternate current paths which can result in collateral tissuedamage.

Although the subject apparatus has been described with respect topreferred embodiments, it will be readily apparent to those havingordinary skill in the art to which it appertains that changes andmodifications may be made thereto without departing from the spirit orscope of the subject apparatus.

While several embodiments of the disclosure have been shown in thedrawings, it is not intended that the disclosure be limited thereto, asit is intended that the disclosure be as broad in scope as the art willallow and that the specification be read likewise. Therefore, the abovedescription should not be construed as limiting, but merely asexemplifications of preferred embodiments. Those skilled in the art willenvision other modifications within the scope and spirit of the claimsappended hereto.

What is claimed is:
 1. An electrosurgical instrument, comprising: a housing having a shaft attached thereto, the housing including a fixed handle and the shaft including a longitudinal axis defined therethrough; a first jaw member movable relative to a second jaw member, the first jaw member attached to the shaft and relatively movable from a first open position wherein the jaw members are disposed in spaced relation relative to one another to a second closed position wherein the jaw members cooperate to grasp tissue therebetween; a drive assembly disposed within the housing and configured to impart movement of the first jaw member between the first and second positions upon actuation thereof; and a handle assembly having a moveable handle defining a pistol-grip configuration with the fixed handle of the housing, the moveable handle operably coupled to the housing and configured to actuate the drive assembly, wherein a combination of mechanical linkages including each of the fixed handle, the housing, and first and second links is configured such that actuation of the movable handle relative to the fixed handle results in relative pivoting between each of the mechanical linkages and at least another one of the mechanical linkages to longitudinally translate the drive assembly to thereby move the first jaw member between the first and second positions, and wherein the drive assembly is substantially aligned along the longitudinal axis and each of the mechanical linkages is substantially disposed on the same side of the longitudinal axis.
 2. The electrosurgical instrument according to claim 1, wherein the drive assembly and the handle assembly cooperate to generate a closure pressure between the first and second jaw members in a range of about 3 kg/cm² to about 16 kg/cm².
 3. The electrosurgical instrument according to claim 1, wherein the combination of mechanical linkages cooperate with a compression spring of the drive assembly to control a closure force provided by the jaw members.
 4. The electrosurgical instrument according to claim 1, wherein the combination of mechanical linkages is a four bar mechanical linkage.
 5. The electrosurgical instrument according to claim 3, wherein one of the first or second links is urged into the compression spring upon actuation of the movable handle relative to the fixed handle.
 6. The electrosurgical instrument according to claim 5, wherein the drive assembly further includes a drive member operably coupled to the first jaw member, and wherein the compression spring is configured to selectively offset motion of the one of the first or second links to control the closure force.
 7. The electrosurgical instrument according to claim 1, further comprising a plurality of pivots, each pivot directly pivotably coupling one of the mechanical linkages with another one of the mechanical linkages, the plurality of pivots substantially on the same side of the longitudinal axis as the mechanical linkages.
 8. The electrosurgical instrument according to claim 7, wherein at least one of the pivots is a floating pivot relative to the housing and at least another one of the pivots is a fixed pivot relative to the housing. 